Black Label's 4D8 2.5-Piece Chromoly Crankset uses a 2.5-piece design that requires only one spindle bolt, therefore saving weight and increasing strength. The light and tough chromoly crankarms have regular and nano-drive sprocket bolt holes. This fine crankset is designed for Mid bottom brackets with a 48-spline, 19mm axle, and is right and left hand-drive compatible.