Wilson Staff Men's D100 Golf Iron Set Optimized head proportions throughout the iron set deliver ideal launch angles, ball speeds and spin rates for each loft Wilson Staff's D-100 family utilizes lightweight technology to increase distance by achieving faster ball speeds with the same swing effort 7% thinner iron face delivers faster ball speeds and unsurpassed distance Exoskeleton technology used with an undercut cavity allows 35% more mass to be moved to the sole, heel and toe areas for extreme forgiveness