Soft Comfort CorPaks Hot or Cold Therapy Packs are the perfect solution to help relieve headaches, ease pain, and help reduce inflammation associated with strains, sprains, and other soft tissue injuries. Conveniently store packs in the freezer for cold therapy the moment you need it! These packs stay soft and flexible, comfortably contouring to painful areas. Use cold to help reduce inflammation; warm packs in the microwave to aid muscle relaxation and to promote healing. The pack's exterior is made of a proprietary blend of synthetic fibers and organic plant materials. The Soft Comfort CorPaks contain more nontoxic, biodegradable fill than traditional packs to retain cold and heat longer. The soft, frost free pack is gentle on skin and does not need to be wrapped in a towel. WARNING: Do not sit on or place excess weight on pack.