THE MEDTHERAPIES AIRPRENE KNEE BRACE provides a perforated "neoprene" to allow moisture to escape skin area. Features and Benefits of The Medtherapies Airprene Knee Brace * Perforated "neoprene" to allow moisture to escape skin area. * Two medial and two lateral spiral stell stays for additional support * Univeral buttress pad for easy adjustment and exact fit. * Tapered in back for comfortable fit. * Piping along thigh and calf areaas of support to stop flexing. * Criss-cross strapping above & below the knee for patella stabilization. SIZING: Measure around the center of the knee with leg extended: Small: 12.5" - 14.5" Medium: 14.5" - 16" Large: 16.5" - 18" XLarge: 18.5" - 20" XXLarge: 20.5" - 22"