Perfect for the continuous treatment of an injury at home where you have access to a microwave or freezer. The pack is ideal for treating a wide range of injuries and they last longer than a standard instant hot or cold pack. Use warm for effective relief from muscular and joint aches and pains and cold for reducing swelling and inflammation. The pack will remain flexible at low temperatures. Simply keep the pack in the freezer to use cold or heat in the microwave to use hot. We recommended that you wrap the pack in a cloth or sleeve when applying the pack directly to the skin.