Transcutaneous Electrical Nerve Stimulator Model: ST-304

K221092 · Shenzhen Future Electronic Co., Ltd. · NUH · Sep 13, 2022 · Neurology

Device Facts

• Record ID: K221092
• Device Name: Transcutaneous Electrical Nerve Stimulator Model: ST-304
• Applicant: Shenzhen Future Electronic Co., Ltd.
• Product Code: NUH · Neurology
• Decision Date: Sep 13, 2022
• Decision: SESE
• Submission Type: Traditional
• Regulation: 21 CFR 882.5890
• Device Class: Class 2
• Attributes: Therapeutic

Indications for Use

To be used for temporary relief of pain associated with sore and aching muscles in the back of neck, due to strain from exercise or normal household and work activities. - Neck Pad is used in back of neck.

Device Story

Body-worn, home-use transcutaneous electrical nerve stimulator (TENS); model ST-304. Device features two titanium (Gr.2) electrodes applied to back of neck. Input: user-adjusted intensity (1-15 levels) and mode (2 stimulation modes) via push-button controls. Operation: rechargeable lithium battery powers boost converter circuit; PWM control modulates voltage amplitude and frequency to deliver low-voltage electrical pulses to nerves. Heating function provides constant 32-38°C. Output: electrical pulses for pain relief; heating for comfort. Used by patients for 10-minute sessions. Benefits: temporary muscle pain relief. Healthcare provider does not operate; patient self-administers.

Clinical Evidence

Bench testing only. No clinical data provided. Safety and effectiveness demonstrated through electrical safety, EMC, biocompatibility (ISO 10993-5/10), and software verification/validation testing.

Technological Characteristics

Materials: Titanium (Gr.2) electrodes, ABS plastic/silica gel housing. Energy: 3.7V DC rechargeable lithium battery. Principle: TENS via low-voltage electrical pulses; PWM-controlled boost converter. Form factor: wearable neck device. Connectivity: None. Sterilization: Not stated. Software: Microprocessor-controlled, non-adaptive.

Indications for Use

Indicated for adults for temporary relief of pain associated with sore and aching muscles in the back of neck due to strain from exercise or normal household and work activities.

Regulatory Classification

Identification

A transcutaneous electrical nerve stimulator for pain relief is a device used to apply an electrical current to electrodes on a patient's skin to treat pain.

Predicate Devices

• Neck Care Therapy (K210756)
• Neck Care Therapy (K172897)

Reference Devices

• DR-HO'S Electro Therapy Conductive Gel (K200402)

Submission Summary (Full Text)

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September 13, 2022

Shenzhen Future Electronic Co., Ltd % You Yijie Manager Oimmig Medical Consulting Service Co., Ltd RM. 1711, Building K, No. 101 Science Ave International Creative Valley Guangzhou, Guangdong 510663 China

Re: K221092

Trade/Device Name: Transcutaneous Electrical Nerve Stimulator Model: ST-304 Regulation Number: 21 CFR 882.5890 Regulation Name: Transcutaneous electrical nerve stimulator for pain relief Regulatory Class: Class II Product Code: NUH Dated: August 12, 2022 Received: August 12, 2022

Dear You Yijie:

We have reviewed your Section 510(k) premarket notification of intent to market the device referenced above and have determined the device is substantially equivalent (for the indications for use stated in the enclosure) to legally marketed predicate devices marketed in interstate commerce prior to May 28, 1976, the enactment date of the Medical Device Amendments, or to devices that have been reclassified in accordance with the provisions of the Federal Food, Drug, and Cosmetic Act (Act) that do not require approval of a premarket approval application (PMA). You may, therefore, market the device, subject to the general controls provisions of the Act. Although this letter refers to your product as a device, please be aware that some cleared products may instead be combination products. The 510(k) Premarket Notification Database located at https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfpmn/pmn.cfm identifies combination product submissions. The general controls provisions of the Act include requirements for annual registration, listing of devices, good manufacturing practice, labeling, and prohibitions against misbranding and adulteration. Please note: CDRH does not evaluate information related to contract liability warranties. We remind you, however, that device labeling must be truthful and not misleading.

If your device is classified (see above) into either class II (Special Controls) or class III (PMA), it may be subject to additional controls. Existing major regulations affecting your device can be found in the Code of Federal Regulations, Title 21, Parts 800 to 898. In addition, FDA may publish further announcements concerning your device in the Federal Register.

Please be advised that FDA's issuance of a substantial equivalence determination does not mean that FDA has made a determination that your device complies with other requirements of the Act or any Federal

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statutes and regulations administered by other Federal agencies. You must comply with all the Act's requirements, including, but not limited to: registration and listing (21 CFR Part 807); labeling (21 CFR Part 801); medical device reporting of medical device-related adverse events) (21 CFR 803) for devices or postmarketing safety reporting (21 CFR 4, Subpart B) for combination products (see https://www.fda.gov/combination-products/guidance-regulatory-information/postmarketing-safety-reportingcombination-products); good manufacturing practice requirements as set forth in the quality systems (QS) regulation (21 CFR Part 820) for devices or current good manufacturing practices (21 CFR 4, Subpart A) for combination products; and, if applicable, the electronic product radiation control provisions (Sections 531-542 of the Act); 21 CFR 1000-1050.

Also, please note the regulation entitled, "Misbranding by reference to premarket notification" (21 CFR Part 807.97). For questions regarding the reporting of adverse events under the MDR regulation (21 CFR Part 803), please go to https://www.fda.gov/medical-device-safety/medical-device-reportingmdr-how-report-medical-device-problems.

For comprehensive regulatory information about medical devices and radiation-emitting products, including information about labeling regulations, please see Device Advice (https://www.fda.gov/medicaldevices/device-advice-comprehensive-regulatory-assistance) and CDRH Learn (https://www.fda.gov/training-and-continuing-education/cdrh-learn). Additionally, you may contact the Division of Industry and Consumer Education (DICE) to ask a question about a specific regulatory topic. See the DICE website (https://www.fda.gov/medical-device-advice-comprehensive-regulatoryassistance/contact-us-division-industry-and-consumer-education-dice) for more information or contact DICE by email ([e-mail]) or phone [phone] or 301-796-7100).

Sincerely,

Pamela D. Scott Assistant Director DHT5B: Division of Neuromodulation and Physical Medicine Devices OHT5: Office of Neurological and Physical Medicine Devices Office of Product Evaluation and Ouality Center for Devices and Radiological Health

Enclosure

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### Indications for Use

510(k) Number (if known)

K221092 Device Name

Transcutaneous Electrical Nerve Stimulator Model: ST-304

Indications for Use (Describe)

To be used for temporary relief of pain associated with sore and aching muscles in the back of neck, due to strain from exercise or normal household and work activities.

- Neck Pad is used in back of neck.

Type of Use (Select one or both, as applicable)

| Prescription Use (Part 21 CFR 801 Subpart D)

X Over-The-Counter Use (21 CFR 801 Subpart C)

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# 510(k) Summary

### 1. Submitter's Information

### Establishment Registration Information

Name: SHENZHEN FUTURE ELECTRONIC CO.,LTD Address: Bldg B. Qiangchengda Industrial Park, No. 30, Youtian Road, Longgang SHENZHEN Guangdong, CN 518116 Registration Number: 3014344342

### Contact Person of applicant

Name: Zhao Qihong Address: Bldg B. Qiangchengda Industrial Park, No. 30, Youtian Road, Longgang SHENZHEN Guangdong, CN 518116 TEL: [phone] FAX: [phone] Email: [e-mail]

### Contact Person of the Submission:

Name: Yijie You Address: RM.1711, Building K, No.101 Science Ave International Creative Valley Development Zone, Guangzhou China TEL: [phone] FAX: [phone] Email: [e-mail]

Date prepared: Mar. 4, 2022

### 2. Device Information

| Trade Name: | Transcutaneous<br>stimulator | electrical | nerve |
|--------------------|---------------------------------------------------------|------------|-------|
| Model: | ST-304 | | |
| Regulation name: | Stimulator, Nerve, Transcutaneous, Over-<br>The-Counter | | |
| Review Panel: | Neurology | | |
| Product Code: | NUH | | |
| Regulation Class: | II | | |
| Regulation Number: | 21CFR 882.5890 | | |

## 3. Predicate Device Information

### Primary Predicate Device

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| 510(k) submitter/holder: | Shenzhen OSTO Technology Company Limited |
|--------------------------|-----------------------------------------------------|
| 510(K) Number: | K210756 |
| Trade Name: | Neck Care Therapy |
| Model: | AST-905H |
| Classification name: | Stimulator, Nerve, Transcutaneous, Over-The-Counter |
| Review panel: | Neurology |
| Product code: | NUH |
| Regulation Class: | II |
| Regulation Number: | 21 CFR 882.5890 |

### Secondary Predicate Device

| 510(k) submitter/holder: | Shenzhen OSTO Technology Company Limited |
|--------------------------|-----------------------------------------------------|
| 510(K) Number: | K172897 |
| Trade Name: | Neck Care Therapy |
| Model: | 905B |
| Classification name: | Stimulator, Nerve, Transcutaneous, Over-The-Counter |
| Review panel: | Neurology |
| Product code: | NUH, NGX |
| Regulation Class: | II |
| Regulation Number: | 21 CFR 882.5890, 890.5850 |

## 4. Device description

The subject device is intended to use on back of neck and it designed accord with human body cervical physiological curvature of streamlined ring design. It is a body-worn and home-use device. It uses low-frequency electronic therapy and designed to temporary relief of pain associated with sore and aching muscles in the back of neck. It only has one model: ST-304.

The trade name of the subject device is Transcutaneous electrical nerve stimulator.

The Transcutaneous electrical nerve stimulator (model: ST-304) consists of a main unit and Type C-USB charging cable. The main unit consists of shell, lithium battery (only 1pcs), neck electrodes pads (a pair of fixed neck electrodes pads), lower shell connector and control buttons and silicone pads. There are two fixed neck electrodes pads on the main unit. The material of neck electrodes pads is titanium material (Gr.2). There are only 1 pcs lithium battery in-build in main unit. The model of lithium battery is KRL 103040.

The neck electrodes pads (a pair of fixed neck electrodes pads) are a kind of Titanium material, and the detail content as following description and as the classify of ASTM F67 2017 it is under Gr2:

| Titanium material (Gr.2) | Value |
|--------------------------|-------|
|--------------------------|-------|

| Content | |
|-----------------|-----------|
| Main Components | Ti |
| | Remainder |

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| | | Al | / | | |
|--|-------------------|------|--------|-------|-------|
| | | V | / | | |
| | Impurity Elements | Fe | 0.235 | | |
| | | C | 0.008 | | |
| | | N | 0.012 | | |
| | | O | 0.130 | | |
| | | H | 0.0043 | | |
| | Other Impurities | each | ≤ 0.1 | total | ≤ 0.3 |

The Transcutaneous electrical nerve stimulator (model: ST-304) power supply is 3.7V DC using built-in lithium battery(1200mAh). The built-in lithium battery can be recharged. But the power adapter (Input: 100-240V~, 50/60Hz,0.7A, Output: 5V== 1000mA) is not the parts of the subject device so it shall be supplied by the user. There are two fixed neck electrodes pads on the main unit. The material of neck electrodes pads is Titanium material (Gr.2).

The following power adapter is recommended:

Manufacturer: ShenZhen RiHuiDa Power Supply Co., Ltd

Model: RHD 10W050100U

UL certificate: E474213 Specification: Input: 100-240V ~, 50/60Hz,0.7A Output :5V = 1000mA

The Transcutaneous electrical nerve stimulator (model: ST-304) totally has 3 modes. The stimulation has 2 modes for stimulating and 15 output Intensity Levels for each mode, so the device can give certain electrical pulse through the neck electrodes pads on the intact skin of back neck to help users to temporary relief of pain. The heating only has 1 mode for

heating and it can also provide a constant temperature of 32℃ to 38℃ to provide a

warming sensation. The stimulation function and heating function can be used separately or simultaneously. The neck electrodes pads provide users with back of neck stimulation and heat to warm and comfort the muscles of the back of neck.

The main unit provides access to adjust the intensity up or down and adjust stimulating mode, put ON/OFF the main unit and heating function.

The Intensity level of electrical stimulation and heating function are easily controlled by the end user using manual, push-button controls. The push-button controls are consisted of four button which are Switch on/off button/mode switch button, heating button, Intensity increase button and Intensity decrease button.

Button function description:

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Switch on/off button/mode switch button(

- 1) Long press about (2 seconds) to turn on or turn off the Transcutaneous electrical nerve stimulator (model: ST-304) and sound "Di". When turn on the device or in the working condition the button indicator light is blue and turn off the device button indicator will close.
- 2) When battery is low capacity(<3.5V ), the indicator of the button will be flashing in blue light 3 times for 5 seconds and with long "Di" sound every two minutes. At the same time when short press the button will sound "Di". When the battery is charging the button will be flashing in green. When the battery is charged the button will be in green light always. The device can't be used when it is charging.
- 3) When the capacity of battery<3.1V, the device shown prompt sound, shut down.
- 4) Pulse mode adjusted:

Short press the button( Di, Di-Di-Di-Di-Di-Di-Di" sound about 3 second will be heard .When Mode 2 is chosen, intermittent " Di-, Di-, Di-, Di-- " sound for 3 seconds will be heard.

# Heating button(纽

1) Short press the button to start heating and button indication is green. If start heating successfully, the Transcutaneous Electrical Nerve Stimulator (ST-304) will sound "Di". Short press to stop heating and button indication lights off, if stopping heating successfully, the Transcutaneous Electrical Nerve Stimulator (ST-304) will sound "Di Di".

Intensity increase button (

- 1) Short press " = ", " " " " " button to add or subtract pulse intensity, 1-15 level adjustable. Level 1 is the lowest intensity and the Level 15 is the highest intensity.
- 2) After press " " "or " " " " " " " button, the sound "Dit" will be heard. When turn on the device, there is

without any pulse output, after short press " ■ " one time then enter into the working condition and will be output pulse in level 1 intensity. When the Intensity increase to 15 level, then short press the" = " one more time will sound "Di Di", it means the device is in the highest Intensity level (15 Intensity level).

The default stimulation time is 10 minutes, and the user cannot adjust but could turn off the device during working condition.

Transcutaneous electrical nerve stimulator (model: ST-304) has 2 types stimulation modes: Mode 1, Mode 2.

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When turn on the device, the device turns into default setting, the stimulation mode is Mode 2 and there is without any pulse output, after short press " " one time then enter into the working condition and will be output pulse at level 1 intensity.

These stimulation modes can be selected by short pressing the Switch on/off button/mode switch button

( ( ). The two stimulation modes are the same in indication for use.

Before use the device to wipe the Electro Therapy Conductive Gel on the Neck Electrode Pads. But the Electro Therapy Conductive Gel is not the part of subject device so it shall be supplied by the user.

The following Electro Therapy Conductive Gel are recommended:

Manufacturer: Guangzhou Xinbo Electronic Co., Ltd.

Trade/Device Name: DR-HO'S Electro Therapy Conductive Gel

Model Name: DHGEL

FDA clearance with a 510(k) number: K200402

### Accessory

| Name | Specification/model | Quantity(pcs) |
|-------------------------------|------------------------------|---------------|
| Type C -USB<br>charging cable | length 1m,<br>24AWG(0.16*11) | 1 |

### Principle of operation:

The Transcutaneous electrical nerve stimulator (model: ST-304) sends low-voltage electrical pulses to specific nerves via two fixed neck electrodes pads applied on the intact skin of back of neck and powered by rechargeable lithium battery. The purpose is to temporarily relieve pain. By adjusting the output voltage and frequency to produce the low-voltage electrical pulses and achieve the effect of electrotherapy. Voltage regulation is realized by the Boost Converter circuit, which controls the voltage amplitude by modifying the PWM control circuit. After that, the voltage is released to the electrode through the analog circuit, and the time change of the output voltage is controlled by modifying the PWM frequency to achieve the specific electrotherapy effect.

Note: PWM means Pulse Width Modulation

## 5. Indications for Use

To be used for temporary relief of pain associated with sore and aching muscles in the back of neck, due to strain from exercise or normal household and work activities.

- Neck electrodes Pads is used in back of neck.

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## 6. Summary of technological characteristics of device compared to the predicate devices (K210756 and

## K172897)

| Characteristic | Subject device<br>(Transcutaneous<br>Electrical Nerve<br>Stimulator, model ST-<br>304) | Predicate device 1<br>(K210756, Neck Care<br>Therapy, model: AST-<br>905H) | Predicate device 2<br>(K172897, Neck Care Therapy,<br>905B) | Discussion of difference | |
|-----------------------------------------------------------------------------------------------|-----------------------------------------------------------------------------------------------------------------------------------------------------------|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|-----------------------------------------------------------------------------------------|-----------------------|
| Manufacturer | Shenzhen Future<br>Electronic Co., Ltd | Shenzhen OSTO Technology<br>Co., Ltd | Shenzhen OSTO Technology<br>Co., Ltd | / | |
| Picture | Image: Subject device | Image: Predicate device 1 | Image: Predicate device 2 | / | |
| Classification | 21 CFR 882.5890 | 21 CFR 882.5890 | 21 CFR 882.5890, 21 CFR<br>890.5850 | Same | |
| Prescription/OTC | OTC | OTC | OTC | Same | |
| Product Code | NUH | NUH | NUH, NGX | Same | |
| FDA Class | II | II | II | Same | |
| Intended Use & Indications<br>for Use | To be used for temporary<br>relief of pain associated<br>with sore and aching<br>muscles in the back of<br>neck, due to strain from<br>exercise or normal | To be used for temporary<br>relief of pain associated with<br>sore and aching muscles in<br>the shoulder, waist, back of<br>neck, back,<br>arm, and leg, due to strain | To be used for temporary relief<br>of pain associated with sore and<br>aching muscles in the shoulder,<br>waist, back of neck, back, | Same<br>Both of subject device and<br>predicate devices can be used in<br>back of neck. | |
| Characteristic | Subject device<br>(Transcutaneous<br>Electrical Nerve<br>Stimulator, model ST-304) | Predicate device 1<br>(K210756, Neck Care<br>Therapy, model: AST-905H) | Predicate device 2<br>(K172897, Neck Care Therapy, 905B) | Discussion of difference | |
| | household and work activities.<br>- Neck electrodes Pads is<br>used in back of neck. | from exercise or normal<br>household and work<br>activities.<br>- Neck Pad is used in back of<br>neck.<br>- Meridian Pad is used in<br>shoulder, waist, back, arm<br>and leg. | arm, and leg, due to strain from<br>exercise or normal household<br>and work activities.<br>- Neck Pad is used in back of<br>neck.<br>- Meridian Pad is used in<br>shoulder, waist, back, and arm. | | |
| target population | adults | adults | adults | Same | |
| Power Source | Main Unit: 3.7Vdc,<br>1200mAh Rechargeable<br>lithium battery<br>Power Adaptor:<br>Input: 100-240V~,<br>50/60Hz,0.7A<br>Output :5V $=$ 1000mA | Main Unit: 3.7Vdc,<br>2200mAh lithium battery<br>Power Adaptor:<br>Input: 100~240Vac,<br>50/60Hz, 0.2A;<br>Output: 5Vdc, 1A<br><br>Remote Control:<br>Battery: 3Vdc, 1.5V, AAA x<br>2 | Main Unit:<br>Power Adaptor:<br>Input:100~240Vac,50/60Hz,<br>0.2A;<br>Output: 5Vdc, 1A<br>Battery: 3.7Vdc, 500mAh<br><br>Remote Control:<br>Battery: 3Vdc, AAA x 2<br>Unit Input: 5Vdc,1A | Different<br>See D1 | |
| Method of line<br>current isolation | Type BF Applied<br>Part | Type BF Applied<br>Part | Type BF Applied<br>Part | Same | |
| Patient<br>Leakage<br>Current | Normal<br>condition | AC:23.3 $\mu$ A<br>DC: $\le$ 1 $\mu$ A | AC:54.5 $\mu$ A<br>DC:0.5 $\mu$ A | AC:54.5 $\mu$ A<br>DC:0.5 $\mu$ A | Different<br>See D2 |
| | Single fault | AC: 6.7 $\mu$ A, | AC:120.0 $\mu$ A | AC:120.0 $\mu$ A | Different |
| Characteristic | Subject device<br>(Transcutaneous<br>Electrical Nerve<br>Stimulator, model ST-304) | Predicate device 1<br>(K210756, Neck Care<br>Therapy, model: AST-905H) | Predicate device 2<br>(K172897, Neck Care Therapy,<br>905B) | Discussion of difference | |
| condition | DC: $\u2264$ 1 \u03bcA | DC:0.6 \u03bc A | DC:0.6 \u03bc A | See D2 | |
| Average current through<br>electrodes when device is<br>on but no pulses are being<br>applied | < 0.01 \u03bc A | < 0.01 \u03bc A | < 0.01 \u03bc A | Same | |
| Number of Output<br>Modes | 3 | 3 | 2 | Same | |
| Output Intensity Level | For stimulating:15<br>For heating:1 | For stimulating:50<br>For heating:3 | 50 steps | Different<br>See D3 | |
| Heating temperature | 32-38°C | 30-40°C | NA | Different<br>See D4 | |
| Number<br>of Output<br>Channels | Number<br>1<br>Synchronous<br>or<br>Alternating? | 1<br>Synchronous | 1<br>Synchronous | Same | |
| Method of<br>Channel<br>Isolation | Voltage Transform<br>Isolation | Voltage Transform<br>Isolation | Voltage Transform<br>Isolation | Same | |
| Regulated Current or<br>Regulated Voltage? | Voltage Control | Voltage Control | Voltage Control | Same | |
| Software/Firmware/Microprocessor Control? | Yes | Yes | Yes | Same | |
| Automatic Overload Trip? | No | No | No | Same | |
| Automatic No-Load Trip? | No | No | No | Same | |
| Characteristic | Subject device<br>(Transcutaneous<br>Electrical Nerve<br>Stimulator, model ST-304) | Predicate device 1<br>(K210756, Neck Care<br>Therapy, model: AST-905H) | Predicate device 2<br>(K172897, Neck Care Therapy, 905B) | Discussion of difference | |
| Automatic Shut Off? | Yes | Yes | Yes | Same | |
| User Override Control? | Yes | Yes | Yes | Same | |
| Indicator | On/Off Status? | Yes | Yes | Yes | Same |
| Display | Low Battery? | Yes | Yes | Yes | Same |
| | Voltage/ Current<br>Level? | Yes | Yes | Yes | Same |
| Timer Range<br>(minutes) | 10min | 5-30 min | 5-30 min | Different<br>See D5 | |
| | ANSI AAMI ES60601-1<br>ES60601-1:2005/(R)2012<br>and A1:2012,<br>C1:2009/(R)2012 and<br>A2:2010/(R)2012<br>(Consolidated Text) | Yes | Yes | Yes | Same |
| | ANSI AAMI ES60601-1-<br>2 :2014 | Yes | Yes | Yes | Same |
| | IEC 60601-2-10 Edition 2.1<br>2016-04 | Yes | Yes | Yes | Same |
| Weight | 145g (only main unit) | For Main Unit:<br>AST-905H: 178g<br>For Electrode:<br>Patch Electrode: 44g | Main Unit:<br>AST-905B: 222g<br>Electrode:<br>Patch Electrode: 44g | Different<br>See D6 | |
| Dimensions (mm)<br>(W x H x D) | Main unit: 145 (W) × 140 (L) × 53 (H) (mm) | AST-905H:<br>173.4*156.3*43.4 mm<br>For Electrode: | Main Unit:<br>AST-905B: 187.2*169*67.3 mm<br>Electrode: Patch Electrode: 8.9 | Different<br>See D7 | |
| Characteristic | Subject device<br>(Transcutaneous<br>Electrical Nerve<br>Stimulator, model ST-<br>304) | Predicate device 1<br>(K210756, Neck Care<br>Therapy, model: AST-<br>905H) | Predicate device 2<br>(K172897, Neck Care Therapy,<br>905B) | Discussion of difference | |
| | Neck electrode pad:<br>$3,0cm×4,0cm$<br>Effective area for each<br>Neck electrode<br>pad: $10cm²$ | Meridian Pad: $8.9*5.8cm$<br>Effective area: $50.04cm²$<br>Neck Pad: $42.3 mm x29.5$<br>mm | cm $*5.8 cm$ | | |
| Housing Materials and<br>Construction | For Neck electrode pad:<br>Titanium material (Gr2) | For Electrode Pads:<br>White silica gel, Black<br>conductive silicone,<br>Transparent<br>conductive adhesive<br>silicone, Transparent<br>PET silicone<br>For Neck Pad: Stainless<br>steel | Electrode Pads:<br>White silica gel, Black conductive<br>silicone, Transparent conductive<br>adhesive silicone, Transparent<br>PET silicone<br>Sticky metal sheet: Stainless<br>steel | Different<br>See D8 | |
| | For Unit Housing: ABS<br>Plastic and silica gel | For Unit Housing: ABS<br>plastic | Housing unit: ABS plastic | | |
| Characteristic | Subject device<br>(Transcutaneous<br>Electrical Nerve<br>Stimulator, model ST-304) | Predicate device 1<br>(K210756, Neck Care<br>Therapy, model: AST-905H) | Predicate device 2<br>(K172897, Neck Care Therapy, 905B) | Discussion of difference | |
| Waveform | Mode 1:<br>Pulsed, symmetric, biphasic<br>Mode 2: Pulsed, symmetric, biphasic | Pulsed, symmetric, biphasic | Pulsed, symmetric, biphasic | Same | |
| Shape (e.g., rectangular, spike, rectified sinusoidal) | Mode 1:<br>Rectangular, with interphase interval<br>Mode 2:<br>Rectangular, with interphase interval | Rectangular, with interphase interval | Rectangular, with interphase interval | Same | |
| Maximum Output<br>Voltage (± 10%) | Mode 1:<br>$44V @ 500 Ω$<br>$80V @ 2 kΩ$<br>$112V @ 10 kΩ$<br>Mode 2:<br>$42V @ 500 Ω$<br>$78V @ 2 kΩ$<br>$105V @ 10 kΩ$ | $44V±10% @ 500 Ω$<br>$80V±10% @ 2kΩ$<br>$112V±10% @ 10kΩ$ | $44V±10% @ 500 Ω$<br>$80V±10% @ 2kΩ$<br>$112V±10% @ 10kΩ$ | Different<br>See D 9 | |
| Maximum Output<br>Current (± 10%) | Mode 1:<br>$88mA @ 500 Ω$<br>$40mA @ 2 kΩ$ | $88mA @ 500 Ω$<br>$40mA @ 2 kΩ$<br>$11.2mA @ 10 kΩ$ | $88mA @ 500 Ω$<br>$40mA @ 2 kΩ$<br>$11.2mA @ 10 kΩ$ | Different<br>See D10 | |
| Characteristic | Subject device<br>(Transcutaneous<br>Electrical Nerve<br>Stimulator, model ST-<br>304) | Predicate device 1<br>(K210756, Neck Care<br>Therapy, model: AST-<br>905H) | Predicate device 2<br>(K172897, Neck Care Therapy,<br>905B) | Discussion of difference | |
| | 11.2mA @ 10 KΩ | | | | |
| | Mode 2:<br>84mA @ 500 Ω<br>39mA @ 2 KΩ<br>10.5mA @ 10 KΩ | | | | |
| Pulse Width | Mode 1:<br>120 μ s ± 10% | 120 μ s | 120 μ s | Same | |
| | Mode 2:<br>120 μ s ± 10% | | | | |
| Frequency | Mode 1:<br>77.3Hz ±10% | 77.3Hz | 77.3Hz | Same | |
| | Mode 2:<br>77.3Hz ±10% | | | | |
| Net Charge (µC/pulse) | Mode 1:<br>0 µC @ 500Ω<br>Method: balanced<br>waveform | 0 µC @ 500Ω<br>Method: balanced waveform | 0 µC @ 500Ω<br>Method: balanced waveform | Same | |
| | Mode 2:<br>0 µC @ 500Ω<br>Method: balanced<br>waveform | | | | |
| Maximum Phase Charge<br>(μC) | Mode 1:<br>10.3µC@ 500Ω<br>Mode 2: | 10.56 (µC) @ 500Ω | 12.78 (μC) @ 500Ω | Different<br>See D 11 | |
| Characteristic | Subject device<br>(Transcutaneous<br>Electrical Nerve<br>Stimulator, model ST-304) | Predicate device 1<br>(K210756, Neck Care<br>Therapy, model: AST-905H) | Predicate device 2<br>(K172897, Neck Care Therapy,<br>905B) | Discussion of difference | |
| | 9.6μC@ 500Ω | | | | |
| Maximum Current Density,<br>(mA / cm², r.m.s.) @ 500Ω | Mode 1:<br>2.2mA/cm² | 0.0326 mA/cm² | 0.235 mA/cm² | Different<br>See D 12 | |
| | Mode 2:<br>2.2mA/cm² | | | | |
| Maximum Average Power<br>Density (mW/cm²) | Mode 1:<br>0.36mW/cm² @500Ω | 0.0000266mW/cm² @500Ω | 1.38 mW/cm² | Different<br>See D 13 | |
| | Mode 2:<br>0.32mW/cm² @500Ω | | | | |
| Burst<br>Mode<br>(i.e.,<br>pulse<br>trains) | Pulses per burst | N/A, no burst mode | Not public | Not public | Different<br>See D14 |
| | Bursts per<br>second | | | | |
| | Burst duration<br>(seconds) | | | | |
| | Duty Cycle [Line<br>(b) x Line (c) | | | | |
| | | | | | |
| | ON Time (seconds) | 240u s ± 10% | Not public | Not public | Different<br>See D 15 |
| | OFF Time (seconds) | 12.8ms ±10% | Not public | Not public | Different<br>See D 16 |
| Characteristic | Subject device<br>(Transcutaneous<br>Electrical Nerve<br>Stimulator, model ST-<br>304) | Predicate device 1<br>(K210756, Neck Care<br>Therapy, model: AST-<br>905H) | Predicate device 2<br>(K172897, Neck Care Therapy,<br>905B) | Discussion of difference | |
| Operating Environment | Temperature: 10~38°C<br>Humidity: 30% -75%RH<br>Atmospheric Pressure:<br>860 hPa -1060 hPa | Temperature: 10~40°C<br>Humidity: 15% - 90%RH<br>Atmospheric Pressure: 700<br>hPa to 1060 hPa | Temperature: 5~40°C<br>Humidity: 15% - 90%RH<br>Atmospheric Pressure: 700 hPa<br>to 1060 hPa | Different<br>See D 17 | |
| Storage Environment | Temperature: -25~70°C<br>Humidity: ≤90%RH<br>Atmospheric Pressure: 860<br>hPa -1060 hPa | Temperature: -25~70°C<br>Humidity: ≤90%RH<br>Atmospheric Pressure: 860<br>hPa -1060 hPa | Temperature: -25~70°C<br>Humidity: ≤90%RH<br>Atmospheric Pressure: 860 hPa<br>-1060 hPa | Same | |
| Biocompatibility | Biocompatibility test<br>according to ISO 10993-5<br>and ISO 10993-10 | Biocompatibility test<br>according to ISO 10993-5<br>and ISO 10993-10 | Biocompatibility test according to<br>ISO 10993-5 and ISO 10993-10 | Same | |
| Electrical Safety | Comply with ANSI AAMI<br>ES60601-1: 2005/(R)2012<br>and A1: 2012 and<br>IEC60601-2-10 Edition 2.1<br>2016-04 | Comply with IEC 60601-1<br>and IEC 60601-2-10 | Comply with IEC 60601-1 and<br>IEC 60601-2-10 | Same | |
| EMC | Comply with ANSI AAMI<br>IEC 60601-1-2:2014 | Comply with IEC 60601-1-2 | Comply with IEC 60601-1-2 | Same | |

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Output Specifications – Comparison with Predicate Devices

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#### The discussion of differences exist between the subject and predicate device is listed in following:

- D1: The subject device has demonstrated electromagnetic compatibility and electrical safety by ANSI AAMI ES60601-1 and ANSI AAMI IEC 60601-1-2 testing. Therefore, the difference does not raise the issue of product's safety and effectiveness.
- D2: The subject device has demonstrated electrical safety by passing ANSI AAMI ES60601-1 and IEC 60601-2-10 tests. Therefore, the difference does not raise the issue of product's safety and effectiveness.
- D3: The subject device and predicate devices have differences in Intensity Level for stimulation modes. However, both of subject device and predicate devices have the same indications, frequency, waveform, shape and pulse width. The Maximum Output Voltage and Maximum Output Current of subject device under stimulation modes are equivalent and with the same range as that of the predicate devices.

The heating level of subject device is only one but the Heating temperature range of subject device is within the range of that of the predicate device1(K210756, Neck Care Therapy, model: AST-905H).

Furthermore, the subject device has demonstrated electrical safety by passing ANSI AAMI ES60601-1 and IEC 60601-2-10 tests.

Therefore, the difference will not affect the safety and effectiveness of the subject device compared to the predicate device.

The heating temperature range of subject device is within the range of the predicate device 1(K210756, Neck Care Therapy, model: AST-905H).

- D4: The subject device has demonstrated electrical safety by passing ANSI AAMI ES60601-1 and IEC 60601-2-10 tests. Therefore, the difference will not affectiveness of the subject device compared to the predicate device.
- D5: The timer range of subject…