Excellent choice for thumb sprains and CMC arthritis. Features & Benefits: Triple stays: encompasses the thumb to provide a secure environment following injuryMalleable stays: main, dorsal and palmar stays can all be adjusted to customize for each patientPerforated suede: improves evaporative abilityPolypropylene felt: wicks moisture away from skinVelstretch strap: properly secures base of product while allowing ulnar and radial deviationFits left or right: reduces inventory needsUS manufacturing: higher quality control standards MediumFits: 4 1/8" - 4 5/8"