X.P.S.S.? (eXtreme Performance Shifting System), the acronym that refers to the most efficient system ever, lets you shift with extreme speed and incredible precision. full-carbon unidirectional-multidirectional cranks - light alloy fixing bolts - light alloy chainrings with XPSS? (eXtreme Performance Shifting System) - chainrings with hard anodization treatment - 8 pins on the large chainring - integrated ULTRA-TORQUE? semi-axles - requires ULTRA-TORQUE? BB cups.