Callaway Golf X Hot Pro Irons Set, New face technology combines precise control of face thickness and undercut depth; Allows for a blend of power and solid feel demanded by better players 20 Close Spaced V Groove; Developed to create the most precise grooves we have ever put in an iron of this type Feel Management Technology; Produced through a dual material medallion that fine-tunes sound and promotes a crisp, dynamic feel at higher ball speeds New Project X 95 Flighted Shaft; Lightweight 95 gram shaft highlights a lighter overall club configuration thats designed for more speed and control