This Robinson Racing Products pinion gear is machined from hard blackened steel for durability in small-scale drivetrain applications. It is a 17-tooth design built to 0.5 modulus pitch with a 2mm bore, sized for micro and mini-class RC vehicles. Includes a set screw collar for secure motor shaft mounting. Features: Hard blackened steel construction 17 tooth, 0.5 modulus pitch 2mm bore Includes set screw collar 7/7/26 cs