The race-engineered Shimano RC903 S-PHYRE Wide Cycling Shoes feature the same high-performance technology as its regular width version, but with a wider fit for riders who seek a bit of extra space. Using DYNALAST technology, a proprietary last built specifically for wide-width shoes, you are provided with a fit that conforms to the natural contours of your foot to allow for a smooth, efficient upstroke. An anti-twist heel cup in the shoe's footbed stabilizes your heel when you put down max watts, while its optimum stiffness levels maximize your power transfer and reduce energy loss.