Relief Pak Cold and Hot Donut Compression Sleeve compress 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 pack in microwave to make warm, or chill in freezer to make cool. Each pack comes with a compression sleeve to wear between the pack and your skin. Pack is non-toxic.