Comfortable patella stabilizer/knee support provides moderate protection from lateral injuries. Open-knee buttress keeps patella in place but does not restrict knee movement. Neoprene w/ top and bottom straps. Fits both knees. For sizing, measure around knee: SM: 12"-14" / 30-35 cm MD: 14"-16" / 35-40 cm LG: 16"-18" / 40-45 cm XL: 18"-20" / 45-50 cm