For external gear systems, 21-24 gears. Crank arms made of aluminium, sprocket-wheels made of steel. Mounted chain guard. Fits bicycles with square tapered spindles and 113 mm crankshaft length. Number of sprocket-wheel teeth: 22-32-42. Crank arm length: 170 mm. Pedal thread 9/16". Mainly used for Mountain Bikes.