For treatment of arthritis, sports injuries and repetitive strain. Designed for soothing warmth and comfort. Provides support and temporary relief of painful tendons and joints. Supports yet provides good grip. Flexible stay keeps thumb in neutral position. Fits either thumb. How ThermaDry3 works: Unique three-layer construction; first layer is Hydrolon terry which wicks moisture away from skin to keep you dry and comfortable. Perforated Hypolan blend middle layer is comfortable, cushioned and breathable, provides light compression which helps counteract tissue swelling. Durable nylon outer layer retains body's own heat, to naturally increase blood flow to damaged or painful joints and muscles to help encourage healing and pain relief. Antimicrobial. LG/XL fits 7-1/2" - 10" (19-25 cm) wrist circumference.