Robinson Racing Extra Hard Blackened Steel 32 Pitch Pinion gears are built to last. Made from high carbon steel and then heat treated to increase the hardness of the surface even more. High carbon steel is naturally higher in lubricity and lower in adhesion than milder grades of steel making these gears ideal for use with metal spur gears. Can be run on motors using a 5mm motor shaft including Traxxas, Associated, and HPI models or for any heavy duty application. Standard 1/8 shaft motors will require a 5mm to 1/8 inch Reducer Sleeve (RRP1200).