Grabber Foot Warmers are thin, comfortable, air-activated warmers that fit in your shoe or boot, and provide over five hours of soothing warmth beneath your feet. The latest addition to the best-selling Grabber line, these foot warmers contain a revolutionary warmer technology. Warmers are standard equipment for skiers, snowboarders, hunters, campers, hikers, birdwatchers, or anyone who enjoys outdoor activities when the weather is cold. Warmers are widely used for portable, long-lasting heat therapy. If you suffer from cold, sore feet and toes as a result of Arthritis, Raynaud's, Lupus, Scleroderma, Sjögren's, Myalgia, or just poor circulation, Grabber provides soothing warmth.Features: Measurements: Small/Medium-3" x 9"; Medium/Large-3.5" x 10" Duration: 5+ hours Average Temperature: 95 degrees F Maximum Temperature: 102 degrees FSize chart: S/M: Women size 5-8; Men size 4-7 M/L: Women size 9+; Men size 8+