-Chris Doyle pro model frame. Made with 100% heat treated Sanko 4130 chromoly tubing with double butted top and down tube, Mid BB shell, integrated post clamp, 45x45 internal headset head tube and 5mm thick peg sized dropouts. Weight: 4.85lbs.. Headset and bottom bracket sold seperately. Please note that the 20.5/21" sizes have seat stay brake mounts and the 21.25" has chain stay brake mounts.