Duroc 37 Super-Duty rim, a double wall rim with 2.7mm thick bead hooks Constructed of 6061 Series alloy with a welded seam SRX cartridge bearing straight pull hubs with a 3 pawl alloy cassette body and 24 tooth ratchet ring, yielding 72 engagement points Built with double butted Wheelsmith spokes and alloy spoke nipples Each wheel includes tubeless tape, valve and a 2oz bottle of STR sealant Rear wheel includes XD and Shimano Micro Spline driver bodies