1. Features: 2. Usage method: Press and hold the button for about 3 seconds to turn on the machine. When the temperature is relatively high, the output is voltage, and the red light will come on at this time. After around 5 minutes, it will automatically adjust to medium temperature, and the green light will come on. Press the button to control the temperature adjustment among high - medium - low. Press and hold the button for about 3 seconds to turn off the machine. 3. It is relatively convenient to use. You can use a 5V 2A power supply. Put it directly into clothes such as scarves for heating. The power supply can be a computer, a power adapter or a mobile power supply (the power supply is not included in the accessories). 4. USB power supply: Connect this scarf to a mobile power supply to keep warm at times. It can also be connected to a USB interface for convenient use (the mobile power supply is not included in the package). 5. The maximum temperature is approximately 55 degrees Celsius (131 degrees Fahrenheit). The temperature can be adjusted between 35 - 55 degrees Celsius. 6. It is not recommended that you, infants or people who are not sensitive to heat use it. Do not use it in a relatively humid environment. Please dry it before use. It is not advisable to use it in an unmanned room. 7. Product material: Polyester fiber. 8. Charging method: USB charging. 9. Package contents: 1 USB heated scarf