Profile have been making arguably the best cranks for the last 25 years or more. Made in the USA. The arms are 4130 chromoly and the spindle is a heat treated Cr-mo 48 spline (Hollow cr-mo. Still the best cranks around and they now come with the flush bolt upgrade as standard in new colours for 2009. If you unsure on crank arm size; the 'standard' size is 175mm - it's used by 99% of riders. Sold as arms, spindle, spacers and tool only. Specs: Spindle diameter: 19mm Drive Side: RHD, LHD BB: Not included Colour: Black, Chrome, Raw, Orange. Weight: 2.2lbs Length: 175mm Spindle: Standard Hollow Cr-mo Drive side: RHD and LHD.