3/16″ open patella with superior felt buttress pad. Two each medial and lateral spiral stays are flexible and prevent rolling. Opposing 2″ loop-lock straps above and below patellar opening. 12 1/2″ long. For patellar subluxation, tendonitis, chondromalacia and patellar dislocations. Specify size: (knee circumference) Small 13″-14″; Medium 14″-15″; Large 15″-17″; X-Large 17″-19″.