The Thermoskin Carpal Tunnel Brace with Dorsal Stay has a metal splint positioned at 25Degree under the wrist and an additional dorsal splint on the top side of wrist and hand. With the metal splint positioned at 25 degrees and additional top side splint the wrist is protected from movements that can lead to Carpal Tunnel Syndrome. The adjustable velcro locking straps gives this brace a better fit. The exclusive Trioxon lining increases circulation to aid in the treatment of repetitive stress injuries (RSI) and Tendonitis. Thermoskin Thermal Supports utilize the exclusive Trioxon lining that is clinically proven to capture your natural body heat. Unlike other products, Trioxon allows your skin to ventilate and remain comfortably dry even with long-term use. Competitive products trap the perspiration resulting in discomfort, slippage, risk of infection and unpleasant odor. The Trioxon lining creates a microclimate to help the skin breathe while still providing effective heat therapy. This is the secret of Thermoskin"s long-term comfort for the user. You can even wear Thermoskin for extended periods of time without the discomfort you would have with other products. How Thermoskin works: The application of prolonged heat therapy to the effected area is a simple and quick form of treatment. Heat therapy promotes healing by opening up the small blood vessels, increasing blood flow and facilitating the removal of inflammation. Heat therapy assists your body"s natural healing process. The combination of this heat therapy along with the support and light compression provided by Thermoskin Thermal Supports help prevent, treat and rehabilitate soft tissue injuries. Sizing Guide: Measure the circumference around the wrist joint. X-Small 4 1/2 - 5 1/4 inches. Small 5 1/2 - 6 1/4. Medium 6 1/2 - 7 1/2. Large 7 3/4 - 8 3/4. X-Large 9 - 10. XX-Large 10 1/4 - 11 1/4.