This is the optional MIP Spline CVD Kit for the Traxxas Revo 3.3 and the E-Revo. FEATURES: Steel construction INCLUDES: Two Female Bones Two Male Bones Two Couplings Two Drive Hubs Mounting Hardware REQUIRES: Installing on vehicle jxs 06/08/11 ir/jxs REQUIRES: Installation on the vehicle SPECS: Length: Width: Height: Diameter: (If applicable) COMMENTS: (Any special application or something it will not work with?)