High-strength split one-piece machined 2-gear 13/17T pinion gear module from tough 7075 T6 aluminum and especially difficult coated for superior energy, light-weight, and high durability. Developed on a special gear device, all pinions feature ultra-precise enamel shaping and ultra-true operating for vibration-free operation. Fine interior threading permits easy installation. Each pinion is okay etched because of the tooth number for fast & effortless identification.