SHIMANO Deore XT 11-Speed Mountain Bicycle Disc Brake Freehub - FH-M8010 Double contact bearing seals Super polished bearing races for low friction rolling 12mm E-thru Axle system designed to be durable enough for all-mountain riding while remaining light enough for XC racing Center Lock disc brakes provide reliable braking power Cone races ground by a Cubic Boron Nitride tool for smooth rolling durability