Large Fits Knee Circum. 15 - 16.5 (measurement Taken Just Under The Knee Cap While Knee Is Slightly Bent) Elastic Support For Prevention Treatment & Rehabilitation Of The Knee Thermoskin Elastics Can Expand Contract And Stretch And Are Made Of A High-grade Durable Material That Permits A Full Range Of Movement And Are Comfortable To Wear During A Range Of Activities Anatomically Designed The Elastic Support Will Comfortably Contour To The Shape Of Your Knee It Provides Even Compression And Support To Weakened And Injured Knees It Has Side Stabilizers To Provide Increased Medial And Laterial Support