Fits all 3 Differentials: Front, Center and Rear. Precisely CNC machined from Billet 7075-T6 Aluminum to fit factory Differential case/housing & Differential Gear to ensure minimal wear on differential components. Individually balanced and designed to endure massive centripetal force under speed runs. Easily swap in and out with factory differential components going from unlocked to locked setup in a matter of minutes. Locking differential forces both left and right wheels on the same axle to rotate at the same speed under nearly all circumstances, without regard to tractional differences seen at either wheel. IDEAL For On/Off Road Speed Runs and/or Specific stunts. Spools made for the following Arrma RCs: Arrma Kraton 8s, Arrma Outcast 8s, Arrma Kraton 6s, Arrma Typhon 6s, Arrma Talion 6s, Arrma Outcast 6s, Arrma Notorious 6s, Arrma Limitless, Arrma Mojave, Arrma Infraction & Arrma Felony.