HotHands-2 Hand Warmers ® is a compact 2.25inch X 4inch warmer designed for gloves and mittens and lasts up to 10 hours. Made in the USA. Item # HH-2Q. What"s in a pack? What makes it work? A. Our HeatMax® family of air activated warmers all contain a mixture of natural ingredients that when exposed to air react together to produce heat. This is accomplished through an extremely fast oxidation (or rusting) process. Ingredients include: iron powder, water, salt, activated charcoal and vermiculite. HeatMax® has perfected the process so that our warmers, depending on the individual product, produce heat anywhere from 100°F to 180°F for duration of 1 to 20+ hours. * * * SHIPPING NOTE * * * A physical address MAY be required for UPS delivery on some quantities.