High-strength split one-piece machined 2-gear 13/18T pinion gear module from tough 7075 T6 aluminum and especially hard coated for superior power, lightweight, and high durability. Produced on a specific gear product, all pinions work ultra-precise enamel shaping and ultra-true running for vibration-free procedure. Fine inside threading enables effortless installation. Each pinion is okay etched due to the enamel amount for fast & easy recognition.