This is the 84.5cm Aluminum Front Centre Driveshaft from Ultimate Racing. It is machined from T6-7075 aluminum and anodized in dark gray.
Being made of aluminum and not steel as the original Mugen, we get more flexibility. This extra flexibility translates into greater traction while smoothing the reactions of the car when accelerating.
In addition, we lighten its weight since the aluminum ones weigh 50% less than the original Mugen steel ones. This rotational weight savings translates into lower fuel consumption and faster acceleration.