The Mizuno Pro 243 is a manufacturing masterpiece – more compact and precise than its predecessor, yet faster from the face and more satisfying at impact. Grain Flow Forged HD: One-piece Grain Flow Forged HD from 1025E Pure Select mile carbon steel at Mizuno's iconic facility in Hiroshima, Japan. Where Mizuno irons have been produced since 1968. 4120 Chromoly with Flow Microslot: Featured in the 4-7 irons, a wider, longer micro-slot to create a more expansive high energy area in each club face.  Resulting in a higher flight and faster ball speeds. 1025E Pure Select Mild Carbon Steel 8-GW: Solid feel and control where most wanted, with modern lofts to maintain even distance gapping through the set. Copper Underlay: Thin copper layer beneath a nickel chrome to provide a further enhanced impact feel Wrap-Around Sole Grind: Heavy relief around the sole for improved turf interaction and seamless transition from micro-slot 7 iron into traditional 8 iron construction. Compact Player's Profile: Dramatically reduced topline and blade length throughout the set. Increased Bounce: Another direct request from the tour.  Increased by a degree in the long irons and 2 degrees in the scoring irons for improved turf interaction. Harmonic Impact Technology: Fine tuned head geometry delivers ideal impact feel and feedback Grain Flow Forged Chromoly: Our strongest Forged material with the solid, soft consistent feel of Grain Flow Forged Micro Slot Technology: Milling the head from the sole up creates a Micro-slot that activates the strength of the 1025 Boron material for added distance and increased forgiveness Satin Nickel Chrome Finish : An elegant, yet durable, non-glare finish.