Freeze or Micrwave. Convenience. Multiple use include pain management,postoperative,inflammation,swelling,headaches/migraines,stress/tension,traumatic injuries. Reusable,washable, easily disinfected. Specailly formulated gel. Remains pliable when cold. Does not crystallize,separate, or slump. Nontoxic. Frost free. Biodegradable. Eliminates shock to skin. Becomes softer with use. Specifically designed for use on the neck and shoulder areas. Also works great as a wrist or ankle wrap. (6"x20")