Hi Curtis! the GuideRails support reduces excess shin and heel rotation to keep your natural knee motion in a safe range so you can run with more comfort and less pain. This holistic support system allows your body to embrace its natural motion path while limiting excess motion. The system is made of two firm pieces of foam on either side of the heel. On the inside of the heel, the foam reduces the rolling of the foot inward. On the outside of the heel, the foam is both firmer and higher, reducing the shifting of the heel in the outward direction. Compared to the Progressive Diagonal Rollbar, this is located directly under the foot. For maximum support, we recommend the Addiction GTS 15 or the Beast '20.