BSD's Back Street Pro Hub was designed around their custom driver that boasts a skip free mechanism while keeping the shell compact. The hub shell is built from 6061-T6 alloy & drilled for 36 spokes that's paired with a 14mm 4140 heat-treated chromoly making a reliable & super tough pairing. The Back Street Pro also features chromoly cones & hefty 6903 bearings to keep it rolling smooth. section Product Specs HUB TYPE: Cassette AXLE: Female Bolts DRIVER: 9t DRIVE SIDE: Right Side Drive SPOKE HOLES: 36h WEIGHT: 484g (1.07lbs)