Callaway X Hybrid Woods. New for 2007. Callaway's X Series stainless steel hybrids provide the ultimate in hybrid performance with X Series styling and playability. Borrowing from Callaway's X Series drivers and fairway woods, the X Hybrids incorporate a Modified X-Sole design, cutting through any thick rough while sliding smoothly over tight fairways. The X-Sole design also lowers the leading edge to help get the ball airborne quickly and easily. Increased perimeter weighting and an optimized centre of gravity raise the Moment of Inertia (MOI) for greater stability on off-centre hits resulting in straighter shots while also optimizing ball flight. VFT (Variable Face Thickness) Technology maximizes ball speed and perimeter weighting for more distance and forgiveness. S2H2 technology increases discretionary weight by removing it from the hosel and repositioning it in the perimeter of the clubhead. Much more forgiving and easier to hit than traditional long iron, the 18 degree replaces 2 iron, 21 replaces 3 iron, 24 replaces 4 iron, 27 replaces 5 iron