All-mountain SLX HollowTech II chainset is tough and aggressive yet also lightweight and excellent valueThe HollowTech II Chainset features hollow forged crank arms which are both lightweight and rigid whilst being incredibly strong and durableHollowTech II integrated bottom bracket design uses a wide bearing placement with a large axle diameter for increased stiffness, efficiency and added durabilityTriple version comes with a drilled steel and carbon composite construction middle ring for excellent rigidity and durability10-speed Dyna-Sys chainringsHG-X chainring with patented spike pins give smooth and fast gear shifts under loadWe recommend that the bottom bracket is initially installed by a bike shop to ensure perfect facing and fitFor use with 10-speed HG-X MTB chains onlyComes complete with bottom bracket for 68 and 73 mm frames