Shimano's Deore XT M8120 12-Speed Single Crankset uses an entirely new construction, with exchangeable direct mount chainrings matched to their proven Hollowtech 2 bottom brackets (sold separately) to create a lightweight, strong and great value crankset. Hollow-forged crank arms are incredibly strong, lightweight and deliver maximum power transfer Exchangeable direct mount chainring design can be swapped between single/double combinations 55mm chain line for use with frames with Boost 148mm rear axle spacing Chainring not included ? sold separately (image for illustration purposes only) Bottom bracket sold separately The Deore XT M8120 uses Shimano's long-standing Hollowtech II construction, giving you a crankset that is lightweight, stiff and incredibly durable. They are also a breeze to install and maintain. The versatile direct mount chainring design means you can quickly and easily swap between double or single chainring combinations, boosting the cranksets versatility. This version is sold as bare crank arms, so you can choose the chainring ratio to suit your bike, riding style and terrain. Lightweight, durable and versatile, the Shimano Deore XT M8120 12-Speed Single Crankset is perfect for any mountain bike designed to get out in the wilds on rugged terrain.