Provides shoulder immobilization and controlled range of motion for anterior, multi-directional, inferior and posterior instabilities, rotator cuff deceleration, shoulder AC separations and muscle strains. The shoulder brace is designed to stabilize, assist or restrict movement of the shoulder post-injury and post operatively. Pulls the humerus posteriorly as it restricts external rotation and abduction. Elastic straps attach with Velcro at any point, in any direction and with any amount of force. The smooth, controlled assistance or restraint follows the natural movement of the muscles and joints. Chest circumference Non-flex bicep circumference X-Small 34" - 40" 9" - 10.5" Small 36" - 40" 11" - 13" Medium 38" - 42" 13" - 15" Large 42" - 46" 14" - 17" X-Large 46" - 51" 15" - 17"