Cho-Pat's newly patented Dual Action Knee Strap provides an extra dimension of relief for painful and weakened knees. The strap applies pressure upon the patellar tendon below the kneecap to stabilize and tighten up the kneecap mechanism, which improves patellar tracking and elevation and reduces patellar subluxation. It adds further strengthening to the kneecap mechanism by applying pressure on the tendon above the kneecap as well. This tends to reduce the forces of the quadriceps on the patella tendon and erosion of the undersurface of the kneecap due to a possible misalignment of the quadriceps (Q angle). The device's design and construction apply constant dynamic forces to the surrounding areas of the knee reducing the likelihood of overuse syndromes. At the same time, the strap allows for full mobility while providing maximum benefits. Sizing: Measure Circumference at Mid-Kneecap Note: If you are between sizes, we suggest you order the smaller size. For the Shin Splint Compression Sleeve and all the Knitted Compression devices, we suggest ordering a size larger.