The ice bag is made of PVC inner and polyester fabric outer. It enables the water to stay cold and hot. A must-have product for sports injuries, pain relief, muscle aches and first-aid, etc. For cold therapy, just fill the ice bag with two-thirds of ice and water to relieve headaches, bruises, migraines, muscle aches and swelling. For heat therapy, add hot water(not boiling, 50-60 degrees /122 degrees-140 degrees work best ). Price listed is for 6″, welcome inquiries for more sizes(9″, 11″) we have. Orders of 5000 pieces or greater are eligible for sea shipping. 100% guarantee for quality.