Cook Bros Racing Chromo "Dogbone" Crankset100% heat treated tubular Chromoly, ensuring strength and durability. Design: Dual pinch bolts for added security, with wrapping and welding at the pedal bosses for reinforcement. The set includes a 19mm x 6 tooth heat treated Chromoly spindle, spindle bolts, sprocket bolt, and BB sets. Designed for American bottom brackets, suitable for 3 piece crank setups. Constructed from a combination of steel and aluminum 6061 T6, balancing strength and weight.