Box Three Pro Rear Race Hub is their most affordable hub, and yet it is still absolutely packed with pro level features. The Pro Hub is made with a 6061-T6 aluminium hubshell paired with a chromoly steel 10mm axle for strength and durability. It also features a super-fast 120 tooth engagement system, precision sealed bearings and a 6-bolt disc brake rotor mount, all creating a hub that accelerates and decelerates insanely fast. ###section### Product Specs HUB TYPE: Cassette AXLE: 10mm DRIVER: 16T DRIVE SIDE: Right Side Drive SPOKE HOLES: 36h WEIGHT: 445g (0.98lbs) Colour: Black; Size: 10mm