Safe Material:Hot Water Bag used graphene heatsed,soft flannel cover,constant temperature and not so hot,no need to fill water can keep warm for long time.     USB Recharged:Powered by usb,press and hold the power button for 5 seconds to turn on/off,3 adjustable heat temperature,fast heating in one minute.     Lightweight Foldable:The Hot water bag is foldable portable design,highly sealed,easy to carry to anywhere,2 colors for you choice.     Washable:Water and electricity separation design,washable, soft and skin-friendly flannel cover,resistant to dirt and not lint.     Perfect for winter warm gifts,when you have a fever and sprain,it can be used as Christmas Birthday festival gift for mens women and kids.     Ingredients: natural-ingredients