Cobra King RADSPEED XD Left Handed Mens Regular DriverThe RADSPEED XD driver has been designed for speed, forgiveness and maximum slice correction. The XD (Xtreme Draw) is part of Cobra`s Xtreme range of RADSPEED drivers with heal biased Radial Weighting to deliver a faster and straighter, draw biased drive. Radial Weighting (heel biased) Radial weighting originated from an engineering concept called Radius of Gyration, the distance from the clubs centre of gravity to each weight or technology location.