Callaway Big Bertha Diablo Hybrid Dual Runner Sole Ensures cleaner turf interaction and helps lower the leading edge to make the sweet spot more accessible for various skill levels. Head Design The increased perimeter weighting in the all-stainless steel clubhead helps raise the MOI for more stability and forgiveness and provides greater trajectory control Callaway Golf Core Technologies VFT Technology maximizes ball speed and perimeter weighting for more distance and forgiveness; S2H2 increases discretionary weight by removing it from the hosel and repositioning it in the perimeter of the clubhead.