381 Velvet Electric Pain Relief Heating BagVelvet Electric Pain Relief Heating Bag These product has been filled with energy which help us warm for long time after charging for 7 to 12 min it can be used for 2 to 5 hours which is 5 hours for hard warming and 10 hours for quit warming , it is automatic temperature control avoids over heating These products is leak and explosion proof , a protection device is there which avoids the inside air to expansion the product is high strength and fibre