Shimano M4100 Deore 10 Sp Boost Double ChainsetEngineered for maximum performance on every MTB adventure, this double Boost crankset gives you fast acceleration and control on the toughest of rides. It features a hard-wearing forged alloy crank arm construction, which makes it more than capable of handling all the abuse that's associated with all-day epics in the mountains. Shimano has also equipped it with a HollowTech II integrated bottom bracket for increased stiffness, efficiency and added durability.Features: Crank Arm Material: Forged Alloy Use: MTB Speed: 10 speed Number of Chainrings: 2 Chainrings Included: Yes Crank Arm Length: Multiple options available Chainline: 51.8mm Chainring BCD: For use with 148mm O.L.D. frames Chainring Tooth Count: 36/26T 5 Arm or 4 Arm: 4 arm Design: 2-piece Dyna-Sys Compatible: Yes Boost Spacing: Yes Compatibility: 10 speed Dyna-Sys MTB HG-X transmissions Is BB Included: HollowTech II integrated bottom bracketPart Numbers: 170mm: FCM4100BC66; 175mm: FCM4100BE66Technologies: HollowTech II: HollowTech II integrated bottom bracket design uses a wide bearing placement with a large axle diameter for increased stiffness, efficiency and added durability. SG-X Chainring: SG-X chainring with patented spike pins give smooth and fast gear shifts under load. A 2-year warranty is offered with all Shimano products from Chain Reaction Cycles (3 years on Dura-Ace and XTR products).Buy Shimano Components from Chain Reaction Cycles, the World's Largest Online Bike Store.