The original HotHands warmers provide up to 18 hours of 130-140Adeg F warmth in a soft 4"x 5" pack. Air activated and environmentally safe, these warmers are a must for any outdoor trip. HotHands Adhesive Body Warmer lasts up to 12 hours, is disposable, and has a 4 year shelf life. For counter-top box of 371811, 371820 purchase in multiples of 40.