Provides heat therapy for temporary relief of minor muscular and joint aches and pains associated with overexertion, strains, sprains, and arthritis. New design for improved fit. Patented heat cells for deep penetrating heat. Advanced neck pain therapy. Clinically proven to relax tight muscles and enhance flexibility & mobility. Up to 16 hours pain relief. Provides up to 8 hours of heat while you wear it plus 8 hours of pain relief after you take it off. Odor free, discreet and stays in place. Air-activated, one-time use.