One size fits most. BandIT XM features a unique, non-constrictive design consisting of two soft-plastic plates curved to the shape of the forearm. The plates have soft cushioned neoprene on the insides and these rest against one's skin. The two plates are held together by a single piece of hook & loop strap which is attached with a metal rivet. It stimulates the body's natural healing process by increasing blood flow and oxygen, by reducing inflammation and muscle spasm and by producing a subtle warmth at the painful site. It is highly effective in relieving pain commonly associated with Carpal Tunnel Syndrome and Tendonitis. This product introduces the use of magnetic therapy. "Magna-Therapy", as it often is called, utilizes magnetic pads attached to appendage to enhance natural healing in the area of the elbow. Although not yet approved by the U.S. FDA, magnetic therapy is being investigated as a new remedy for many Repetitive Stress Injuries by the National Institute of Health Office of Alternative Medicine Caution Magnetic products should not be used if pregnant or fitted with cardiac pacemaker and /or automatic internal defibillators. Keep out of reach of magnetictically stored data, ie. computers, discks, credit cards, etc.