Modular super light weight aluminum crank Forged AL7050 30mm BB392EVO spindle Hollow construction begins with forging, then precision CNC machining, and finally culminating with an advanced bonding technology Manufacturing process dramatically reduces weight while increasing stiffness Direct mount chainring. Shimano 12sp compatible ring available separately, use BTI #FS2792 Use modular spider tool, BTI #FS0294, for chainring replacement or chainline adjustment Bottom bracket sold separately. 520g