Traxxas 3943X 13-tooth, 32-pitch heavy-duty Pinion gear is machined from hardened steel for extra strength. Includes set screw. Use Traxxas stock and hop-up replacement parts to get the most out of your Traxxas RTR vehicles. This product is made from high quality materials and designed for long-lasting performance. This is replacement hardware for use on Traxxas vehicles; consult your user's manual for exact parts listings.