Press its internal button and the pack instantly begins to warm up. As the liquid gel turns to a crystallized form, it releases warmth. Massage the pack as it heats to ensure it stays pliable. As it cools, it will harden into the shape where it was applied. The pack is reusable.  When the pack has cooled, drop it into hot water to return it to its liquid form. When all the crystals are gone, the pack can be used again or stored to provide instant heat whenever needed time and time again.  Offered in a wide variety of sizes.

Important: Do not microwave.