When the temperature of this product is high, it needs to be connected to a mobile power supply. It will automatically stop heating after unplugging it, which is safe and hassle-free. USB powered. Humanized heating component design, cold component design heating area on the upper and back of the fuselage. Infrared heating, no harmful radiation. One-touch heating, three-level temperature control, and intelligent heating. Quickly heats up in one minute and keeps you warm. It is washable, as long as it is, and the practical power socket is waterproof and heat-insulated. Polyester fabric is comfortable, windproof, warm, antistatic, lightweight and close-fitting. Suitable for outdoor sports. This vest is available in four sizes: Size: S---Bust: 114cm---Shoulder width: 42.7cm---Length: 69cmM----Bust: 118cm----Shoulder width: 43.9 cm----Length: 71cmL----Bust: 122cm----Shoulder width: 45.1cm---- -Length: 73cmXL----Bust: 126cm----Shoulder width: 46.3cm ----Length: 75cm