Hub: Reign 6061 Aluminum Forged then CNC Machined Hub Body w/ 36H, Sealed Bearings throughout the hub and Cassette w/ 9T Driver & 14mm Chromoly Axle * Rim: 36H Double Wall Alloy * Spokes: 14g Stainless Steel * Driver: Heat Treated & CNC Machined Chromoly 1pc 9T Driver w/ 3 sealed bearings * 2 lb 9.7 oz (1.2 kg)