Heat Factory Outdoor Warmer Pack includes six pairs of Hand Warmers that provide up to 10 hours of heat when tucked into caps, pockets and gloves; three pairs of Toe Warmers that provide up to six hours of heat when used in socks, shoes and boots; and, three Large Body Warmers that provide up to 20 hours of heat when inserted into fanny packs and other accessories. Ideal for all outdoor activities, the Heat Factory warmer is a soft, lightweight pouch containing a mixture of iron powder, charcoal, salt and vermiculite. When exposed to the air, an oxidation process takes place that generates heat. Once activated, Heat Factory warmers can even be saved for later use (preferably within a week) if placed in an airtight container. Unopened, the Heat Factory warmer has a shelf life of three years or more.