Progressive face thickness is incorporated throughout the set starting at 2.0 mm in the 2- through 5-iron with golf clubs for sale, 2.3 mm in the 6- and 7-iron, and 2.5 mm in the 8-iron through pitching wedge ishiner. The result is progressively higher COR where you need it in the middle-irons and long-irons, and fantastic feel in the short-irons.