The Shimano RC903PWR S-PHYRE Cycling Shoe is a stiff, high-performance road shoe built for riders seeking any advantage they can get to take it to the next level. It features a lightweight, breathable upper construction that keeps us comfortable and a carbon fiber composite midsole that optimizes power transfer efficiency and stabilizes the foot during any effort. The race-tuned design features a closure system consisting of a BOA Li2 metal dial, a hook-and-loop toe strap, and a Powerzone lace guide, all of which combine to provide us with a customized fit to reduce foot movement and further optimize power output.