Relief Pak Hot Cold Donut Roll-on Compression Sleeve offers heat therapy cold therapy and compression. The roll-on pack is easy to apply and stays in place without straps. The pack provides cold or hot treatment to soothe discomfort from arthritis sprains strains bruises and swelling. Simply heat the pack in the microwave to make warm or chill in the freezer to make cool. Each pack comes with a compression sleeve to wear between the pack and your skin.