This is the optional Tekno RC Big Bone Center Driveshaft and Outdrives for the Traxxas Stampede 4x4. FEATURES: Driveshaft machined from high-quality aluminum, black anodized Hardened steel outdrives Dogbone design will not split, bind, or bend INCLUDES: Driveshaft, two Outdrives, three O-Rings, Pin and Set Screw jxs 08/28/12 ir/jxs