The Titleist 907 D2 driver is based around increasing the moment of inertia or twisting of the club head at impact, particularly on off centre hits, buy moving the weight low and further back in the clubhead. In addition the 3 piece head construction incorporates a new milled aluminium hosel and a high speed beta titanium face insert. The Titleist 907 D2 driver face insert is thinner at the top than at the bottom to promote a higher launch and lower spin rate for longer drives. The D2 version of the 907 incorporates all the features of the D1, with the only difference being that the head design is more of a classic rounded and less triangular shape. This still increases the moment of inertia but also allows the better player to work the ball left and right more than the D1.