Hot Racing differential spool for the TRA 4-Tec 2.0 3.0, Rally VXL, Rustler 4X4, Slash 4X4, Stampede 4X4, and Telluride 4X4. This is located in the differential case, and can be used front or rear to eliminate the differential action. This part is recommended for off-road use only. It is NOT recommended for on-road or high traction conditions.