1/8" neoprene support with choice of adjustable felt horseshoe-buttress or sewn-in tubular buttress to accommodate mild patella tendonitis, chondromalacia, or subluxation. Donut buttress may be trimmed to allow for medial, lateral, or superior buttress. Medial/lateral spiral stays and superior/inferior compression straps provide additioanl stability. Open popliteal available with donut buttress only.