Premium MaterialThe hot water bottle is made of food grade silicone that is soft and durable,odorless, Non-toxic. BPA-Free hot bottle water bag is recyclable. Safe Easy to UseThe hot water bottles for pain relief, Safe and reliable. Leak-proof and explosion-proof. And never fill with boiling water, check stopper for damage and turn upside down for leak test every time. Heating in Microwave OvenThe hot water bottle with cover can be heated in microwave oven with full cold water,Take off the knit cover and fill in cold water,You should heat the bottle in less than 3 minutes. The microwave heating power must be less than 800W. Multi FunctionalThe hot water bottles for pain relief can be used as hot or cold,Hot compresses can relieve knee pain, back pain, menstrual cramps, cold hands and feet. Cold compresses can pains, sports injuries, ,relieve fever and cool down.