This is the replacement 13 Tooth Idler Gear (first speed gear) for the Traxxas two-speed conversion for the E-Maxx - TRAC4000. FEATURES: Steel construction, gun metal in color Replaces a worn or damaged idler gear YOU WILL RECEIVE: One 13 Tooth Idler Gear (first speed gear) REQUIREMENTS: Installation kpm03/06/2008 ir/jxs &