This high-quality Spur Gear allows you to tune the gear ratio of your ARRMA modelFeatures:Strong steel for long-lasting durability in all conditions - Precision manufactured tooth configuration for smooth power transfer and consistent performance - Engineered to provide consistent operation when large-scale brushless motors are supplying the power to your vehicle's drive line Specification: 39 Tooth 1.0 Module Gear PitchIncludes:1 x Spur Gear (39T, Mod1)