PGA's Longest Average Driver - 2011

Who hits the ball the longest, on average, on the PGA tour?  Well, for 2011 it is J.B. Holmes so far.  Holmes has taken over the mantle of the hardest ball masher from perennial champ Bubba Watson.  The 29 year-old from Kentucky is averaging 317.2 yards per drive in 2011 (toward the end of June) and his longest smash has been 339 yards so far.

What club does J.B. use off the tee?  It's a Callaway FT Tour Driver.