Completely redesigned with a fit inspired by our S-Works model this shoe offers performance-enhancing Stiff injection-molded & glass-reinforced sole with generous vent ports at the front & rear: 5.0 stiffness index Performance-enhancing BG features in the outsole & footbed New Lightweight Boa L4 rotary closure & forefoot Velcro strap for on-the-fly tunability & dynamic fit; features a quick-release lace pull Synthetic upper with mesh venting for supple fit Fits 2-bolt SPD & 3-bolt cleat systems Approximate weight: 290g (1/2 pair 42)