The DonJoy Performance BIONIC Knee Support Brace features industry leading support and protection from lateral forces that occur in everyday sport and activity. The unique Hex shaped patella opening provides patella support and stability while articulating more freely as the knee goes through flexion and extension. Asymmetrical hem lines and stretch webbing closure system ensure the proper fit for un-matched comfort and controllable compression. The wrap around design of this knee brace allows for quick, easy on/off without the need to remove shoes. Born from the number one brand in sports medicine worldwide, our bilateral polycentric hinges with hyperextension stops are sure to keep unstable; ligament damaged and sprained knees from getting in the way of performance. How to measure - 1. Stand with your legs shoulder-width apart, legs slightly bent and leg muscles contracted.2. Measure up six inches from the center of your knee with a tape measure, as shown.3. Measure the circumference of your thigh at the 6-inch mark, as shown.4. Measure down six inches from the center of your knee with a tape measure, as shown. Then measure the circumference of your calf at the 6-inch mark.