Mizuno's MP-68 Irons with 3D muscle technology are the next generation of muscleback irons. The innovative 3D muscle is the result of extensive computer optimization to deliver the ideal CG location that is lower and more face-centered, providing a penetrating and workable ball flight for complete shot control. The MP-68 irons also have a Tour Confirmed sole shape that ensures the appropriate amount of turf interaction for pure ball striking. Mizuno's grain flow forging process ensures that the MP-68s provide the best feel and ball control in the game of golf. The stock shaft on these irons is the True Temper Dynamic Gold steel.