The Drytex Hinged Knee Suppoprt Is A Neoprene Alternative Constructed Of A Unique Nylon Core And Polyester Lycrar Fabric That Allows For Improved Airflow * Provides Compression And Support Yet Allows For Breathability Ideal In Warm Weather Climates * Designed For Mild To Moderate Medial Lateral Stability * Measurements Taken 6 Above Mid-patella Knee Joint Line And 6 Below Mid-patella Circumference * Extra Small Fits: Thigh: 13 - 15.5 (33 - 39 Cm); Knee Center: 12 - 13 (30.5 - 33 Cm); Calf: 10 - 12 (25.5 - 30.5 Cm) *