1. This product needs to be connected to a mobile power supply when the temperature is high, and it will automatically stop heating after pulling out the plug, which is safe and non-inductive.USB powered.2. Humanized heating parts design, the cold parts on the back design heating zone.Infrared heating, no harmful radiation.One-key heating, three-speed temperature control, intelligent heating.Rapid temperature rise in one minute to keep warm.Washable, as long as it is a new type, practical power interface with waterproof insulator treatment.Polyester fabric is comfortable, windproof, warm, antistatic, thin and close to the body.Suitable for outdoor sports.3. This vest is available in four sizes:Size:S---Bust:114cm---Shoulder:42.7cm---Length:69cmM----Bust:118cm-----Shoulder:43.9cm----Length:71cmL----Bust:122cm----Shoulder:45.1cm-----Length:73cmXL----Bust:126cm----Shoulder:46.3cm----Length:75cm