Toasti Toes Feet Warmers from Heat Max are designed for the active outdoor sportsman who is on the move. (Not recommeded for people who are stationary for long periods of time.) Great for skiers and ice skaters. An adhesive side sticks to socks. You can expect up to 5 hours of 100 degree warmth. 2 per package. Odorless, nontoxic, and safe. And NO BATTERIES REQUIRED! Be sure to check out our HotHands hand warmers (stock number HM/HAND)