Shimano deore m627 10 speed double chainsetgreat value deore 2 piece design chainset for 10 speed dyna sys mtb hg x transmissions the 2 piece design chainset features an external bottom bracket system that is a lightweight rigid design that is incredibly strong and durableplease note external hollowtech ii bottom bracket is included features lightweight and rigid steel bottom bracket axle sg x dyna sys plus chainrings with patented spike pin give smooth and fast gear shifts under load lightwe