This gear set is designed for Version 2, 3 and 6 Airsoft gearboxes, and is constructed from thermally treated Steel for a tough finish and long lifespan. They offer a range of ratios from 15.05:1 to 22.2:1 and are a complete set included Bevel, Spur and Sector gear. Features: Thermally Treated Steel 16.32:1 Ratio Version 2/3/6 Compatible Bevel, Spur & Sector Gear Nano-Class Treatment Longlife and Tough Reduced Friction Reduced Noise Specification: Unique gear with extremely fine design, and with Nano-Class surface treatment. Significantly improve its anti-fatigue strength and extend service life. Substantially reducing the friction coefficient of the gear. Noise reduction Package Includes: Modify Gear Set