Justin Thomas using unique Titleist prototype irons

Justin Thomas is slow to change his equipment, adopting an “if it ain’t broke, don’t fix it” philosophy to his gear.

“I don't change just to change,” Thomas said from this week’s World Wide Technology Championship at Mayakoba. “If it's working, just keep using it.”

Thomas’ irons most definitely have been working for him. He’s one of the top players on TOUR in that area of the game, having ranked no worse than sixth in Strokes Gained: Approach-the-Green in each of the five previous TOUR seasons, including three consecutive seasons ranked in the top three.

That’s why intrigue abounded when the former FedExCup champion arrived at last month’s CJ CUP @ SUMMIT with a new set in the bag.

The new irons are very similar to the Titleist 620 MB blades he’d had in the bag since 2019, but they bore a unique stamp with Thomas’ initials, signifying that these were built specifically for the reigning THE PLAYERS champion.

Similar to Adam Scott’s 681.AS irons — which shared much in common with his beloved Forged 680 blades — Thomas’ 621.JT irons are, at a glance, very similar to his previous gamers.

This week, he shed a little light on the irons that bear his initials.

Now, “a little” is key here. The maker of the clubs, Titleist, hasn’t announced any future release possibilities of the prototype irons. Conversely, the company hasn’t said the clubs are one-offs just for Thomas.

“Feedback from the best players in the world is a cornerstone of the Titleist R&D process, and these prototype irons (621.JT and 681.AS) have been developed in collaboration with each player to better understand some key design variables such as shaping, sole design and (center of gravity) placement – that ultimately may find their way into future Titleist iron development,” a Titleist spokesperson said. “We look forward to sharing additional updates on these prototypes as we gain feedback and learn more from each player’s experience.”

So, while we wait for additional updates regarding the future of 621.JT (and 681.AS irons), we can at least learn a little more about the irons from JT himself. Thomas said he is just one of several players that Titleist approached, asking if their clubs needed any subtle changes to better suit their preferences.

Thomas famously likes very little offset in his irons. The term refers to how far the leading edge of the club sits behind the hosel at address. More offset gives players more time to square the club at impact. Amateurs’ clubs often have a lot of offset to lessen their dreaded slice. As a general rule, better players prefer less offset, but few go so far as “zero offset,” which Thomas does.

In working with Titleist engineers, Thomas also was keen to dial in the sound and feel of the new irons to complement the “clean look” he likes.

“They came to me and said let's create (a set of irons), anything that you want to change,” Thomas said. “Obviously I loved it, everything about (my irons) already, but the changes are so minor. … It just was about getting the best feeling iron, the best sounding iron. It's one of those clubs that obviously you have to hit it properly for it to be that way, but one of those ones where you kind of hear it and you turn around like, what is that, you know what I mean?”

Thomas indicated engineers experimented with sole grinds and milling techniques and “stuff that's way, way past my pay grade” in order to produce his dream irons.

The result? “They look awesome,” he said.