Mizuno jpx forged irons the jpx900 forged is the 2nd generation of mizunorsquos forged irons to use boron infused steel which allows a soft feeling forged iron to produce higher ball speeds whereas mizunorsquos 1st generation of boron steel irons used a uniform thinner face to generate more distance the jpx900 forged pushes the technology forward with a multi thickness face the jpx900 forged also boasts a milled pocket which enhances energy transfer over a