If these irons were any easier to use, they would swing for you. The new Big Bertha Irons are the ultimate in forgiveness due to its all-steel design and Notch Weighting Technology. Notch Weighting moves mass toward the heel and the toe for increased forgiveness and less distance lost on off-center hits. And thanks to Callaway?s patented technology, these irons even turn your fat shots and off-center hits into great shots. A 360° variable undercut channel improves perimeter weighting and delivers a solid feel. For a low center of gravity, the Big Bertha Irons come equipped with VFT technology that optimizes face thickness to concentrate more weight toward the bottom of the clubhead.