Geoff's irons are custom-stamped simply with "G."

Geoff is also testing a new Prototype Titleist CB 2-iron.

Titleist Brand Ambassador Ben Curtis arrives at the Aronimink range with his new Prototype AP1 irons.

Here's a closer look at the new Prototype AP1s.

Titleist Tour Rep Chris Tuten makes a new Prototype AP2 delivery.

Titleist Brand Ambassador Michael Sim checks in with the team at the Titleist Tour Van.

Brand-new, bubble-wrapped Prototype CB irons ready for assembly Inside the Titleist Tour Van.

The Titleist Golf Club R&D team gathers information during new Prototyope AP2 testing with Titleist Brand Ambassador Jason Dufner.

A set of new Prototype CB irons awaits its owner in the TTV.

Here's the view from the top.