This Hot/Cold Gel Pad is a reusable, flexible gel pad used for hot and cold therapy. The gel pad slides into the lumbar pad of the Vector Lumbar Support, Back Flex Lumbar Brace, and the Maximum Support Lumbar Brace. This pad can also be used by itself for effective relief of muscular pains and joint aches. This multipurpose gel pad can be heated in the microwave or cooled in the freezer. It is recommended to have two or more hot/cold gel pads on hand to ensure consistent therapeutic treatment. While one is in use the other pad(s) can be recharging in the freezer or prepped in the microwave for repeated hot/cold therapy on sore muscles and joints. This gel pad remains flexible at all temperatures to best conform to your body. It is made of a non-toxic gel with a durable outside cover for prolonged use.