This is an optional MIP Spline CVD Kit, and is intended for use with the Traxxas Summit. This MIP CVD™ Kit replaces the stock plastic drive shafts with Hardened High Strength Alloy. MIP Spline technology accommodates both long and short travel suspensions, as well as high power electric applications. Includes 6mm bores for the re-designed output shafts. MIP products feature a Wax Coated, Black Oxide finish, for appearance, durability and protection, and are 100% made in the USA!