Mizuno MP-59 Irons

While the MP-59 is made from steel, 12 grams of titanium are forged into a pocket behind the face of each club. (It's the slightly darker material in the photo above.) Mizuno says the titanium allows the clubs to maintain the ideal amount of thickness behind the impact area for solid feel while automatically redistributing the weight to the heel, toe and sole of the club.

"The more you push the weight out to the perimeter and the thinner you make it in the middle, there's a trade-off with feel," says David Llewellyn, research and development manager for Mizuno USA. "But by using a lower density material we can maintain thickness here and build in a little bit of forgiveness."

Llewellyn says that like all the other MP irons, the MP-59 has very little offset and a thin topline because that's what better players demand.