Here's a close-up of Jimmy's new Prototype MB 5-iron.

"The new ones are in the bag," Scott said, " no question about it." (For more reaction from Scott, check out today's Team Titleist Tour Blog post.)

Marni Ines of Titleist Golf Club R&D delivers a few more sets to the Titleist Tour Van.

And here's a right-handed set of the new Prototype CB irons being worked on in the Titleist Tour Van.

A few of the new Prototype Titleist irons rest comfortably on the floor of the TTV, awaiting new grips.

Can you guess the owner of these new Prototype MB irons?

The custom Cowboy Orange-paintfill and "R" stamping should give it away…

It's Titleist Brand Ambassador Rickie Fowler, of course.

The Titleist Tour Van is a bit more crowded than usual this week, thanks to all the boxes of new Prototype Titleist AP1, AP2, MB and CB irons (712 series).

The new Prototype AP2 irons are already in the bag of Titleist Brand Ambassador Scott Stallings.