PS ii Hinged Knee Brace 429. This professional quality brace features two smooth acting, geared polycentric hinges. It incorporates rubber condyle pads and hyperextension stops to cushion and protect the knee. Our PS II hinge uses state of the art lightweight materials and design including aircraft grade aluminum gears that accommodate the natural gliding action of the knee. The neoprene sleeve provides therapeutic warmth while a sewn-in patellar buttress aids in patellar tracking. It also features a 3/16” thick neoprene sleeve with nylon facing on both sides.