Callaway's X Hot irons have powerful Speed Frame Face
The cavity back design has allowed Callaway's award winning R&D team to place the weight in the X Hot irons to precisely position the centre of gravity, and move the most compliant part of the face, i.e. the sweet spot, lower. Callaway's research found that more and more golfers are striking their irons shot lower on the face, and designed the X Hot iron to produce faster ball speeds from this area. In the X Hot irons, Callaway takes the "Speed Frame Face Technology" it's been using in its drivers and utilized it in irons. That tech is designed to create a better transfer of energy from clubface to golf ball, thereby boosting ball speed and distance performance.These irons also use a Deep Undercut Cavity design to move the center of gravity lower (helping with launch) and move the "hottest" part of the clubface lower, as well.