Mizuno Pro has always been Mizuno's most forward-thinking series - cutting edge engineering concealed within precise playing profiles preferred by the game's elite players. Pro Fli-Hi PRODUCT FEATURES First Nickle Chromoly 4335+ Hollow Body Construction Iron Utilizing the ultra high strength properties of 4335+ in it's heat treated state for a high COR face, and well as, the more malleable untreated state for body, thus allowing a bendable hosel. L-Face Geometry A more optimized welding techniqu