The original HotHands warmers provide up to 18 hours of 130-140° F warmth in a soft 4"x 5" pack. Air activated and environmentally safe, these warmers are a must for any outdoor trip. HotHands-2 provides two portable heat sacks in a compact 2 1/4" x 4" warmer that lasts up to 10 hours. HotHands Adhesive Body Warmer lasts up to 12 hours, is disposable, and has a 4 year shelf life.