The Asterisk Ultra Cell 4.1 knee brace is a hybrid classic, refined and upgraded from the successful 4.0 model. Designed with professional-level protection and comfort in mind, the 4.1 model includes all the advanced features of the 4.0, but with the option to remove the liners for a sleeker fit. This brace is built for serious motocross, supercross, and off-road riders, featuring a patented 3-piece Tele-Tri Patella Cup for easy movement in tighter gear and a highly durable design that’s repairable in the field. The patented Anti-Rotation Tether links the brace to your boot, providing exceptional lower leg stability and reducing the risk of rotational injuries. With A.C.M. Frame technology and the Symmetri-Glide Hinge, the Ultra Cell 4.1 delivers the ultimate combination of strength, mobility, and protection.Sizes:Small: 13" - 14-7/8"Medium: 14-1/4" - 15-3/4" Large: 15-7/8" - 16-7/8"XL: 17"-18"