This is the Castle Creations Mod 1 Pinion Gear with 8mm Bore. Designed to offer a high strength 8mm bore option for large scale vehicles, this Mod 1 pinion has been constructed from carbon steel. This incredibly strong material matched with the precision of being CNC machined and a high wear case-hardened finish gives you a top tier pinion option. Package includes one pinion gear with set screw.