CorPak Hot & Cold Therapy Packs are an effective method for soothing strains, sprains, headaches, and other soft tissue traumas. The packs stay free from frost and can be cooled in a freezer to inhibit swelling and blood flow, or heated in a microwave for muscle relaxation, ultimately stimulating improved blood circulation and healing. Temperature: Hot or Cold Frost Free Without Strap Temperature Release: Quick Soft surface quickly releases hot/cold therapy Remains flexible, comfortably contours body Frost free exterior is gentle on the skin Excellent Hot / Cold Therapy for Sports CorPaks Soft Comfort Hot or Cold Therapy Packs provide immediate relief for headaches, pain and associated inflammation caused by strains, sprains and other soft tissue injuries. Cold therapy helps reduce swelling, while warm packs can relax muscles and promote healing. The packs stay soft and flexible even when frozen, molding to the body for more targeted treatment. Use for sports injuries, post-workout recovery, fever reduction, arthritis and more. The packs are made of a blend of synthetic fibers and organic materials, and contain more biodegradable fill than traditional packs for longer-lasting cold or heat. The durable seam prevents leaks and the pack is gentle on skin without needing a towel. Store in freezer for cold therapy or heat in the microwave according to instructions included. Reusable and latex-free, made in USA. WARNING: Do not sit on or place excess weight on pack.