TruVativ Holzfeller OCT DH Cranksets. Features: AL-7075-T6 anodized black chainring, cold forged and CNC'd with anti-chainsuck features Crank bolts included Forged, 1-piece AL-7050-TV construction Compatible with TruVativ BashGuard Open Core Technology provides hollow forged crank arms that are lighter and stronger than the standard Holzfeller