High-strength split one-piece machined 2-gear 13/18T pinion gear module from tough 7075 T6 aluminum and especially difficult coated for superior energy, light weight, and high durability. Created on a particular gear device, all pinions feature ultra-precise enamel shaping and ultra-true operating for vibration-free operation. Fine interior threading allows effortless installation. Each pinion is okay etched because of the tooth quantity for quick & easy recognition.