This is an optional set of Traxxas Rear Steel-Spline Constant-Velocity Driveshafts, intended for use with 4x4 and 4x4 VXL models of the Hoss, Rustler, Stampede and Slash kits. The driveshafts are engineered to satisfy the performance and durability needs of the most demanding drivers. Designed specifically for monster truck applications, these shafts are built to withstand the brutal torque of Hoss’ 540XL motor and the massive grip of the huge Sledgehammer tires. Traxxas’ unique, splined telescoping design delivers full-range articulation, so there is never a need to limit suspension travel. Since they are made by Traxxas, you can count on easy installation and perfect fit in your Traxxas model.