Shimano Crank Set ´´Alfine´´ FC-S501 Hollowtech II, 170mm crank length, with integrated axle, with 68mm BSA bottom bracket 42 teeth, black, with two chainguard rings.Specifications:- Variation: set- Crank length: 170,0 mm- Amount of chain rings: 1- System compatibility: 8-speed, 9-speed- Bottom bracket: Hollowtech II- Large chain ring: 42 teeth- Material: aluminium