Wilson

The nice thing about continuing down a specific technological path is that with each iteration you learn how to use it to greater
effect. This iron is evidence of that. Learning from its work on its D7 iron, Wilson refined several of its technologies for use in the D9. For several years the company used a series of slots in the sole called “power holes” – polymer-filled cutouts along the sole that contribute to the flexing of the face at impact. A new iteration of power holes was developed through a computerised shape-and-size optimisation process to maximise ball speed and forgiveness across the face. Wilson’s designers looked at the trade-off between forgiveness and centre-of-gravity location. In the D7, the choice was moment of inertia to mitigate the loss of speed on mis-hits, but lowering the centre of gravity height to help get the ball up took precedence here, which required moving weight from the perimeter to lower in the clubhead. The face is still a stamped stainless steel, but how it is welded to the body is significantly different. Instead of being welded entirely on the perimeter of the face, on the D9 it is welded to the outside surfaces of the topline and toe areas, leading to more rebound. 

7-iron loft 27 degrees pw loft 42 degrees