This is an optional K Factory ST-Steel/Aluminum Universal Joint Set, and is intended for use with the Team Magic E4 family of 1/10 touring cars. K-Factory pays close attention to the industry and has developed a set of high strength universal joints that can handle the extremely powerful brushless motors and high voltage lithium batteries that are revolutionizing R/C racing. Unfortunately, the downside to this technology is the additional stress placed on the transmission.
The improved strength that these universal joints provide comes from the use of specially developed K-Factory ST-Steel and an increase in drive shaft thickness. The thicker and stronger universal joint has been combined with a lightweight aluminum wheel adapter helps to reduce the overall weight and keeps the rotating mass of the E4 transmission as low as possible.