Professionally designed with a smooth surface and wide wheel profile for enhanced traction and stability at high speeds. Utilizing Formula Four Urethane, these wheels have unmatched abrasion resistance, controllable grip, and lasting speed on any terrain. Plus, the Lock-In Full Shape provides a wider version of the asymmetrical design, with a conically cut outer wall and "lock-in" cut on the inside for maximum performance. These 99a durometer wheels strike the perfect balance between grip and slide, making them ideal for slick surfaces.