[Durable Safety] The hot water bottles are made of rubber to ensure maximum safety, perfect heat transfer and longer water retention. For added safety, the hot water temperature should not exceed 80C. sealing the hot water bottle is made of thickened PVC liner and spiral sealing cap, which is molded in one piece, effective explosion-proof, waterproof leak-proof, high temperature resistant, soft and skin-friendly, very durable and easy to carry. [Unique Design] This lovely shark plush hot water bottle is double-layered design to make the spasmodic hot water bottle safer and more comfortable. The hot water bottle caps are made of high quality and comfortable materials for longer heat preservation. Widely UsedThese hot water bags are ideal winter heating accessories. They can also be used to relieve pain in the neck and shoulders and keep hands and feet warm, menstrual cramps, hot compresses and cold treatments. They can also be used as birthday gifts, Christmas gifts for family and friends to make them feel your warm love in winter. [Perfect Gift for Her] Our hot water bottles with a soft lid are the best Christmas or birthday gift sets, and the perfect sock filler for women or men. Use all year round