"Ping GMAX 7PC Iron Set - Graphite In the GMax iron, PING engineers have created our longest, straightest model ever utilizing COR-Eye Technology, a revolutionary design that increases face flexing for faster ball speeds across the face to generate incredible distance. The wide sole design positions the CG low/back to maximize forgiveness. Progressive lengths and lofts are optimized for efficient gapping with the distance control and high trajectory you need to hit and hold more greens. Features: SPEED-GENERATING STRUCTURE Activates sole, face (31% thinner perimeter) and top rail to create more flex for increased ball speed (approximately 1-3 mph across face) leading to more distance w/control. CUSTOM TUNING PORT (CTP) CONNECTS TO SOLE Positions CG low/back and increases MOI for greater forgiveness, higher launch and more accuracy. SOLE GEOMETRY Thin sole helps increase face flex. Enhanced leading edge, greater trailing edge relief and increased bounce improve turf interaction. PROGRESSIVE LENGTHS & LOFTS Lengths and lofts are optimized to increase distance with proper gapping and higher trajectories for stopping power. LIGHTER SWINGWEIGHTS IN 4-IRON (C6), 5-IRON (C7) & 6-IRON (C8) Straight-flight technology helps square face at impact for faster ball speeds and straighter results."