A. Features: B. Usage method: Press and hold the button for about 3 seconds to turn on the machine. When the temperature is high, the output is voltage, and the red light will come on at that time. After approximately 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. C. It is 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). D. USB power supply: Connect this scarf to a mobile power supply to keep warm at any time. It can also be connected to a USB interface for convenient use (the mobile power supply is not included in the package). E. The maximum temperature is around 55 degrees Celsius (131 degrees Fahrenheit). The temperature can be adjusted between 35 - 55 degrees Celsius. F. It is advisable not to let yourself, infants or people who are not sensitive to heat use it. Do not use it in a humid environment. Please dry it before use. It is recommended not to use it in an unmanned room. G. Product material: Polyester fiber. H. Charging method: USB charging. I. Package contents: 1 USB heated scarf