Important Safety Information
Legal Disclaimer: Statements regarding dietary supplements have not been evaluated by the FDA and are not intended to diagnose, treat, cure, or prevent any disease or health condition. Consult a healthcare professional before using this device, especially if you have pre-existing medical conditions.
Do not use this device if you have a pacemaker, defibrillator, or other implanted metallic or electronic device. Do not use on broken skin. Do not use while driving or operating machinery. Keep out of reach of children.
Product Overview
The iSTIM S1 is a wireless Transcutaneous Electrical Nerve Stimulation (TENS) unit combined with a heating function, designed for targeted pain relief. It features a compact, wearable design with rechargeable capabilities and adjustable intensity levels.
Package Contents:
- Heat + TENS Combo Unit x 1
- Self-Adhesive Gel Pads x 2 (8 pieces total)
- USB-C Cable x 1
- Instruction Manual x 1
- Quick Guide x 1
- Parking Board x 2 (for storing gel pads)

Image: The iSTIM S1 unit, two packs of gel pads, a USB charger set, a quick guide, and parking boards are shown neatly arranged, indicating the complete product set.
Setup and Initial Use
1. Charging the Battery
Charge the iSTIM S1 device for a minimum of 2 hours using the included USB-C cable and charging block. It is recommended to use the provided charging kit. The device is not compatible with any kind of quick chargers.

Image: A diagram illustrating how to charge the iSTIM S1 device using the provided USB-C cable and wall adapter. The device side is indicated for proper connection.
2. Attaching the Gel Pads
- Remove the film labeled "Device Side" from the gel pads.
- Place the exposed side onto the unit and press firmly with your fingertips to ensure it adheres.
- Slowly remove the clear film from the back of the gel, making sure the gel stays in place.
- Firmly apply the electrode gel pad onto the skin in the desired treatment area.

Image: A visual guide demonstrating the four steps to attach the gel pads to the iSTIM S1 device and prepare it for application on the skin.
Operating the Device
- Attach the device to the treatment area and press the On/Off / Mode button for 3 seconds to turn it on. (If there is not sufficient contact with the body, the device beeps and switches itself off).
- After the device is on, the HEAT function indicator flashes green and begins to heat up.
- Keep short pressing the On/Off / Mode button. The TENS function indicator will flash green. Press the intensity control buttons + / - for TENS intensity adjustment.
- If you only need the TENS function and the HEAT function indicator flashes green too, short press the On/Off / Mode button again to close it.
- The auto shut-off time is 20 minutes. To turn off the device manually, press and hold the On/Off / Mode button for 3 seconds.

Image: A detailed view of the iSTIM S1 device's control panel, highlighting the buttons for power, mode selection (Heat/TENS), and intensity adjustment.
Adjusting Intensity and Heat:
The device offers 15 levels of TENS intensity. Use the + and - buttons to increase or decrease the intensity. The heating function can be activated or deactivated as needed. The heat can reach up to 110°F (43°C) in a few seconds.

Image: A woman is shown wearing the iSTIM S1 device on her lower abdomen, illustrating its application for menstrual pain relief. The image emphasizes the device's compact size and discreet placement.
Maintenance and Storage
Cleaning the Device:
Wipe the device with a soft, damp cloth. Do not use abrasive cleaners or immerse the device in water.
Gel Pad Care:
- After each use, reattach the gel pads to the provided parking boards to maintain their adhesiveness and cleanliness.
- Store gel pads in a cool, dry place.
- Replace gel pads when they lose their stickiness or if they become dirty. Do not use extra electrode gel.

Image: The iSTIM S1 device is shown with its gel pads attached to a parking board, illustrating the recommended storage method to keep the pads clean and adhesive for future use.
Troubleshooting
Device Not Turning On:
- Ensure the device is fully charged. The heat function indicator flashes red if charging is needed.
- Verify that the gel pads are making sufficient contact with the skin.
Weak or No Sensation:
- Increase the intensity level using the + button.
- Check if the gel pads are still adhesive. Replace if necessary.
- Ensure proper placement of the gel pads on the skin.
Specifications
- Model: S1 (FT-615)
- Dimensions: 7.56 x 5.91 x 2.32 inches (Package)
- Weight: 12.31 ounces (Package)
- TENS Intensity Levels: 15
- Heat Function: Up to 110°F (43°C)
- Pulse Frequency: 100Hz
- Battery: Rechargeable Li-ION battery
- Manufacturer: Everyway-Medical
- Origin: Made in Taiwan

Image: A technical drawing of the iSTIM S1 device with measurements, indicating its compact size of 170mm in length and 77mm in width.
Official Product Videos
iStim Wireless Tens Machine - Unboxing and Setup
Video: This video provides an unboxing experience of the iSTIM S1 Wireless TENS Unit, demonstrating the contents of the package and initial setup steps for the device and gel pads.
How Does This TENS Unit and Heating Pad Work?
Video: This video explains the functionality of the iSTIM S1 TENS Unit and its integrated heating pad, detailing how it provides pain relief through electrical stimulation and warmth.
Must Try Heat Tens Wireless Unit Is Rechargeable
Video: This video highlights the rechargeable and wireless features of the iSTIM S1 Heat TENS Unit, showcasing its convenience and effectiveness for pain management.
Warranty and Support
For warranty information and customer support, please refer to the contact details provided in the full instruction manual or visit the official iSTIM website. Ensure to register your product for any applicable warranty benefits.
Additional Information
The iSTIM S1 is U.S. FDA cleared & registered and has clinically proven efficacy for pain relief. It is designed to be subtle, slender, and portable, allowing for comfortable wear under clothes.

Image: A woman is depicted relaxing with the iSTIM S1 TENS unit applied to her lower back, highlighting the device's comfortable and discreet design for everyday use.