The Mizuno JPX 900 Forged iron set is grain flow forged using 1025 Boron. Boron is stronger, thinner, and hotter than the 1025E carbon steel used in the JPX 850 Forged irons. This material allowed Mizuno to move the saved weight around the head to increase forgiveness.
The Mizuno JPX 900 Forged iron set has a new COR Tech Design. The design utilizes a multi-thickness face to increase ball speed on shots hit in the center or off center.
There is a reshaped pocket cavity on the JPX 900 Forged iron set as well. The thinnest areas on the heel and toe of the sole are extended to increase ball speed across the face. Almost 22 grams are redistributed to the Power Frame for stability and forgiveness.