Roscoe Hot and Cold Gel Packs help reduce swelling that causes pain and substitute as ice bags for injuries. When used as a cold packs for therapy, it provides fast first relief for acute soft tissue injuries and other conditions that require cold applications to reduce bruising swelling and pain. When used as a hot therapy it provides long lasting soothing relief. It is a great source of muscle relaxation increasing blood flow to promote healing. It can also be used to soothe arthritis pain. It is the perfect solution to help relieve strains sprains headaches and other soft tissue injuries. This versatile gel pack is reusable and can be cooled in the freezer in as little as one hour or warmed in the microwave / hot water in as little as 50 seconds. This flexible ice pack can be molded to the body part even when frozen. When used as a heat pack, the pack should not be overheated in the microwave. Please follow the directions in the instruction manual.