Medical-Grade Knee Brace for Women & Men,[Adjustable V-Straps & Anti-Slip] Knee Support with Side Stabilizers for Knee Pain,Meniscus Tear,ACL,MCL,Arthritis, Patella Stability for Injuries Recovery - MEDIUM 

 (measure the thigh circumference 4 inches above the center of the knee):
M: 15.7-18.5 inches