This is a Rear Pro-Spline HD Axle pack. Pro-Line is proud to introduce the pre-assembled Pro-Spline HD Axles for the rear of the Slash 4x4, Stampede 4x4, Slash 2wd, Stampede 2wd, Electric Rustler and Rally! The Pro-Spline HD Technology debuted on the Pro-Line PRO-MT Kit and is designed to handle
