Beyond BodiHeat® is an easy-to-use, non-medicated, air-activated heat pad that delivers up to 12 hours of soothing pain relief for sore muscles and joints. This exclusive formula works with your own circulation to spread the warmth further and ease your pain fast. UNIQUE FEATURES: Sooth sore, aching muscles. Relieve back and joint pain. Reduce neck and shoulder pain. Ease knee pain. Ideal for lengthy drives and flights, or long days at the office. Great before or during sports activities or chores. Designed to be worn over clothing.