[Compatible with]Compatible with for Traxxas Rustler 4X4 / Slash 4X4 Platinum / Slash 4X4 Ultimate / Slash 4X4 VXL / Slash 4X4 / Stampede 4X4 Unassembled Kit / Stampede 4X4 VXL / Stampede 4X4.[54T Spur gear size]6878 metal differential is 32P 54T 0.8 metric pitch.[32P pinions size]3 pinions(32P 15T/17T/19T pinions) Inner diameter: 5.0mm/0.196inch, come with a 3.175mm coupler to convert 3 pinions apertures to 3.175mm/0.125inch. so compatible with 5mm or 3.175mm shaft diameter motor.3660 3670 3674 4274 4268 550 540 3650 etc series motor.[Hardened gears kit ]suitable for traxxa slash 4x4 slipper clutch is all metal internal gears for strength.Made of heavy duty hardened steel, long time life span.[Free Style]The speed depends on your gear ration. We provide three different teeth pinion gear to make you more choice in gear ration.colour: as shownMaterial: metalPackage Contents:1 x Slipper clutch1 x 15T Pinion1 x 17T Pinion1 x 19T Pinion3 x Set Screws3 x CouplerOnly the above package content, other products are not included.Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.