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 for cold compress. But please Caution: The hot water bottle rubber is not suitable for Microwave oven heating. Warm Tips: FSA or HSA eligible. 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 bottle. Treating sore muscles, stress or cramps, arthritis, aches and pains, stiff necks, lower back pain, Gifts for women menstrual cramp relief and other common aches by hot compress and can also double up as a cold compress for person with fever or to reduce swelling for minor injuries. Good Christmas gifts for women. 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 classier and more personalized look. The hot pack for pain relief should be replaced after two years of use. And check stopper for wear and tear damage at regular intervals.