The ThermiPaq Hot/Cold Pain Relief Wrap uses a thermal ceramic compound from all-natural, clay-based materials, utilizing radiant energy to create a deep penetrating therapeutic system for hot & cold applications, transferring heat & cold slowly & evenly. The clay-based pad is fully reusable. It can be heated in the microwave and cooled in the freezer. The ThermiPaq Hot/Cold Pain Relief Wrap releases its heat or cold slowly for a deeper penetration of therapeutic relief. For bruising, sprains, or swelling. With a soft, fleece cover & adjustable Velcro strap, the ThermiPaq Hot/Cold Pain Relief Wrap can be secured to necks, shoulders, ankles, knees or elbows, molding to your body for the best, targeted distribution of therapeutic pain relief & injury recovery.