The XD stands for 'extra distance, but TaylorMade say it is more than that. They say each design has been tweaked and tuned up, transforming the club into a more muscular, more forgiving, more powerful version of its former self. Compared to the normal clubs, the XD versions feature a bigger head size, a deeper clubface and a new soleplate design for a deeper CG (Centre of Gravity), resulting in improved launch conditions, a larger sweet spot and larger hitting area above the CG. The R540XD comes with a 400cc head size and is fitted with ultra light graphite shafts to promote a higher trajectory, a longer carry and a faster swing speed. Because they offer such a large hitting area above the CG, players will be able to hit more shots that achieve a high launch angle and low spin-rate, which is the optimum combination for achieving maximum distance. Making a large-headed driver isn't difficult, but a key problem inherent to a large metal wood head is that the CG is too far forward, because it's difficult to achieve the kind of low, deep CG needed. TaylorMade's Inverted Cone Technology, allows for a low, deep CG and contributing tremendously to the overall performance of these new clubs.