The new Big Bertha 2019 irons, combine Callaway's cup-face design with a new internal, multi-material weight system to boost performance. The thin, cup-face design helps spread the sweet spot across a larger portion of the hitting area. Slower-swinging players not only will gain distance on solidly struck shots, they will maintain ball speed more effectively on mis-hits because the face flexes more efficiently at impact. To create a higher launch and further increase forgiveness, Callaway designed each Big Bertha iron with what the company calls a Suspended Energy Core. It is comprised of a uniquely shaped, metal-injection-molded (MIM) internal tungsten weight that pulls the center of gravity lower and away from the face. That promotes higher-flying shots. This results in enhanced ball speed and higher launching shots with better sound and feel. Please contact us if you would like to customize set makeup, lofts, lies, grips, or shafts. Satisfaction and authenticity are guaranteed. Standard Callaway warranty applies.