When Mizuno wants to create a distance monster of an iron, their go-to metal is Chromoly.  The Mizuno JPX921 Hot Metal Pro Irons are the third iteration of Mizuno's Chromoly designed irons, and remarkably, they're now even longer, generating the fastest ball speeds Mizuno has ever seen in any of their irons. 

Mizuno achieved this feat by using two key pieces of the technology.  The first piece is a re-engineered CORTECH face, which is now 0.2mm thinner, and thinner means faster.  The second piece is a seamless cup face design, which flexes and rebounds more, rocketing the ball of the face for explosive distance.

Hitting long, towering iron shots is great, unless they miss their target, so Mizuno packs all the JPX921 Hot Metal Pro power into an extremely stable frame with additional perimeter weighting for added forgiveness on off-center strikes.

The stock shaft and grip are Project X's LZ Black and Lamkin ST Hybrid respectively.

Mizuno JPX921 Hot Metal Pro Irons Feature:

• Hot Metal Pro has a more compact profile with reduced offset compared to standard Hot Metal
• 3rd generation Chromoly irons with re-engineered, 0.2mm thinner CORTECH face for massive distance
• Seamless Cup Face with variable thickness sole design produces greater face flex and explosive ball speed
• Stability frame with additional perimeter weighting and toe bias for added stability and forgiveness on off-center strikes
• Harmonic Impact with 3 additional sound ribs to produce a more solid sensation at impact
• Anti-glare Pearl Brush finish minimizes distractions at address
• Stock Shaft: Project X LZ Black Steel
• Stock Grip: Lamkin ST Hybrid