What do you get when you cross the comfort and support of the Mach with a propulsive Pebax plate? What you see. A shoe that pushes the pace and is built with high-rebound cushioning, the new Mach X is supercharged with a layer of PEBA foam that is 34% more elastic than the Carbon X 3 foam. Softer and snappier than ever, this adaptable shoe is comfortable enough for endurance efforts and responds equally well to pace increases.