Multi-purpose. Advanced muscle pain therapy. Up to 8 hours pain relief. Contoured design with 2-adhesive strips that keep it in place. Deep penetrating heat for long lasting pain relief. Clinically proven to relax tight muscles and enhance flexibility & mobility. Air-activated, one-time use. Patented heat cells for deep penetrating heat. Uses: Provides heat therapy for temporary relief of minor muscular and joint aches and pains associated with overexertion, strains, sprains, and arthritis. Questions? 1-800-323-3383. For most recent product information, visit www.thermacare.com. Just open pouch; starts to warm on its own.