Multi Functional Hot Water Bottle - Thermoplastic material that is recyclable. Advanced thermoplastic holds heat longer than traditional hot water bottles with cover, also works as an ice pack, or cold water bottle. But please Caution: The hot water bottle rubber is not suitable for Microwave oven heating. Easy To Use - Wide mouth is easy to fill and the anti spurt lip of hot water bottle with cover prevent water spitting back out like those old rubber ones. Fill only to two-thirds capacity maximum. It's transparent. No more guesswork about how much hot water is inside. Helpful Assistant - The classic design of this classic hot water bag for pain relief. Treating sore muscles, stress or cramps, arthritis, aches and pains, stiff necks, lower back pain, mothers day gifts for mom menstrual cramps and other common aches and and can also double up as a cold compress for kids with fever or to reduce swelling for minor injuries. Care Instruction - Grid texture makes skin contact safer and more comfortable. Comes with an elegant knitted hot water bag cover to prevent the hot rubber from being in direct contact with your skin to cause burns, plus it has a more classy and personalized look. The hot water bottle rubber should be replaced after two years of use. And check stopper for wear and tear damage at regular intervals.