48P Pinion Gear, 31T:SLH This is a 31 tooth, 48 pitch pinion gear with set screw from traxxas. Features:  steel construction, silver in color. Includes:  one 31 tooth, 48 pitch pinion gear  one 3x4mm set screw (1. 5mm hex size). Specs:  length: . 42" (10. 5mm)  inside diameter: 1/8"  outside diameter: . 69" (17. 5mm). Part number(s) included (in factory packaging): 2431.