Prosmart Heated Vest Polar Fleece Lightweight Waistcoat with USB Battery Pack(Unisex,Black) Heated area includes upper back and lower back Efficient heated design allows the electrically heated jacket warm up rapidly in extremely cold weather. Three temperatures can be selected (Hi, Medium, and Low.) This heated vest also includes a convenient cell phone pocket.10000mAh power bank could also charge your phone . Heated vest is unisex style,flexible, washable, and can easily be worn with your daily attire. No matter where you go , wearing PROSmart heated vest and enjoy up to 12 hours of battery life to keep you warm all day . High quality fleece material with feature of anti-static and washed vertical to let you comfortable .Importantly ,It could be easily worn with your daily attire . Machine washable ? Yes ,please .convenient to use that matters. Zipper pocket design is ideal for mobile phone storage . Three temperature can be selected (Hi-red color ; Medium-white color ; Low-blue color).You could adjust the temp. according to every environment.