Shimano slx m552 10 speed triple chainsetcrankset for the shimano 10 speed dyna sys drivetrain system smaller gear increments offer increased efficiency the middle chainring is made from steelcomposite for more durability the large chainring is made of aluminium and the small one is made of steel the crankset has an amazing shifting performance because of hyperdrive also the integrated bottom bracket saves weight and increases stiffness featuresgreat value 2 piece design chainset for 10