HotHands H163760 Hand Warmer, Air Activated, Up to 10 hr, 15 min to 30 min, 3 1 2 in Lg, 40 PK TRW00113 Made from cast iron and Made from cast iron and featuring an I beam handle NH NST (National Hose National Standard) threads are only compatible with other NH NST threads These hand warmers are worn inside gloves and mittens and give off heat that keep hands and fingers warm Warmer Type Hand Warmer Activation Method Air Activated Heating Time Up to 10 hr Average Temperature 135 °F Number of Hand Warmers Included 40 Length 3 1 2 in Width 2 in Reusability Disposable For Use With Gloves Time to Reach Average Temperature 15 min to 30 min Country of Origin USA