Wilson staff d300 graphite irons are the ultimate distance iron a succession of what wilson determine as power holes are incorporated into the irons and have been filled with teo31 urethane this substance helps the flex at impact to help create incredible distance gains the flx face of the iron acts with a spring effect and as the ball impacts the iron the face it flexes and trampolines the ball off generating greater distance and trajectory the irons benefit from heel toe weighting system