Features 1、Chrome Molybdenum Alloy Steel Material: The gear surface is treated with anti rust treatment, which has strong wear resistance, corrosion resistance, good performance and long service life. 2、Work Smoothly: Compared with other pinions, our 1/10 rc car pinions have good processing, low roughness and noise, making them roll smoothly. 3、Easy Installation: 19T 20T 21T 22T 23T pinion gears have its own fixing screw holes, easy installation, simple operation, and machine screws are provided in the package. 4、Five Different Pinions: Five pinion gears with different numbers of teeth are available, giving you more choices in gear ratios and making your RC car perform better. 5、Applicable Model: The pinion is an ideal replacement for old or damaged originals for a 1/10 rc car 3.175mm shaft motor. Item Type: RC Car Motor Gear Material: Chrome Molybdenum Alloy Steel Product Color: Black Weight: Approx. 25g / 0.9in Number of Teeth: 19T 20T 21T 22T 23T Gear Pitch: 48DP/0.53M Center Aperture: Approx. 3.175mm / 0.13in 19T Size: Approx. 11x9.8mm / 0.43x0.39in 20T Size: Approx. 11.5x9.8mm / 0.45x0.39in 21T Size: Approx. 12x9.8mm / 0.47x0.39in 22T Size: Approx. 12.5x9.8mm / 0.49x0.39in 23T Size: Approx. 13x9.8mm / 0.51x0.39in Application: Suitable for 1/10 RC Remote Control Model Car Package List 5 x Motor Gear 5 x Machine Screw 1 x Wrench