The Mizuno Pro 245 is measurably quicker again from the face than the Mizuno Pro 243 but also easier to launch – due to a complex hollow body construction and internally suspended Tungsten weight. Grain Flow Forged Chromoly: Our strongest Forged material with the solid, soft consistent feel of Grain Flow Forged Hot Metal Blade Design: Grain Flow Forged 4135 Chromoly face and neck (2-8 iron) with multi-thickness configuration and laser welded 431 Stainless steel back piece for elevated ball speeds and launch. Internal Tungsten Weighting (2-7): A suspended 47g tungsten weight is positioned to enable the sole to flex for faster ball speeds, as well as, improve launch. Partial Hollow Scoring Irons: Laser welded partial hollow construction, GFF HD 1025E Select body, with 17-4 back piece for penetrating flight. Copper Underlay: Thin copper layer beneath a nickel chrome to provide a further enhanced impact feel Harmonic Impact Technology: Fine tuned head geometry delivers ideal impact feel and feedback Hybrid Muscle Back: A high performance hollow body hybrid structure is formed by utilizing a Grain Flow Forged Chromoly Face and neck part, fused to multi-material body 1025 Mild Carbon Steel: Soft mild carbon steel for an incredibly soft feel 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.