Notice: Heating When It Be Plugged, Not Retain Heat. Material:Neoprene, skin-friendly, lightweight, warm and stretchy. Adjustble with hook and loop fastner, one size fit most men women and teenagers 3 levels adjustable temperature of 122/ 140 / 158 , adjust according to your needs, safe e, no worry itll scald wrist. Electric heating will warm your wrist and enhance blood circulation reduce knee pain from the deep Electric heater with USB cable, it can be plugged in any power supplies with USB port, such as power bank(5V/2A is recommended), car charger, laptop, desktop computer, etc. Come with a USB cables Portable and Convenient e, you can use it at home, office, hotel, in the car when you are working, watching TV, reading, travel and driving. And also perfect for outdoor activities in cold seasons, such as Cycling, Biking, Motorcycle, Snowboarding, Snowmobile, Skiing, Camping, Hiking, Climbing, Hunting, Fishing, Ice-Fishing, Running, Walking, Trekking, Dance, Yoga and days out Men women old people arthritis rheumatism pain relief wrist warmer with 3 temperature control winter heated warm wrist bandage wrap support thermal therapy for joint soreness, swelling. A great Christmas/New Year/Holiday/Birthday gift for Grandpa, Granny, Dad, Mom, sisters, brothers, wife, husband, friends and yourself