Bicycle B.B. axle, model SC-BB-101, is a cottered bottom bracket axle that carries the crank arms and turns in the bottom bracket bearings. It comes in four versions: B.B. Axle Russian 42-53-46 mm, cottered, in a golden finish. B.B. Axle 37-54-46 mm, cottered, in a black finish. B.B. Axle PH/T 2C, cottered, in a BCP finish. B.B. Axle A8, cottered, with a black centre. Each axle is a stepped spindle with machined bearing shoulders, in gold, black, bright silver and a dark finish with a black centre.