The Mizuno JPX-850 forged iron set feature a new, thinner face that is strategically reinforced by a Power Frame cavity which places weight to the extreme corners of the club head for maximum forgiveness along with increased distance. Mizuno?s new BORON material is 30% stronger than traditional 1025E steel billets which allows for a thinner face and extreme ball speeds. The result is an incredible iron that combines Grain Flow Forged precision and feel with shocking distance. A combination that was unachievable before BORON.