Crankset type: Single or Double chainring setup, made for road / fixie / mountain use. Material: Alloy arms (e.g. aluminum), possibly with alloy chainring(s). Arm length: Usually something like 165-175 mm. Bolt Circle Diameter (BCD): TBD (commonly 144 mm for fixie, 130 mm for road doubles). Speed / compatibility: Likely compatible with 1× or 2× drivetrains depending on configuration. Bottom bracket type: Square taper.