Mystery Wrench: The Answer

Alright folks, prepare to be amazed by the intended use of The Mystery Wrench.



To those that correctly answered that it was a pin wrench, you are correct. As to its intended use, the items I  intend to use it on are these:

Not Pictured: The Accompanying Leopard Print Singlet Rack

Those are a mix of Milo Triplex and Duplex barbells, each with a set of hollow globes intended to contain either an aggregate (sand or lead shot) or a matching set of stacked plates. Unlike modern plate-loading barbells, the globe must be disassembled to change the weight. This disassembly is done via a specially fitted nut.

Wrench goes here.

That, friends, is a task for the pin wrench. Beer will be bought for Natalie and Marie, who correctly guessed the wrench's purpose. For the rest of you, the Stark Center has a wonderful collection of old barbell materials, among which I found this excellent diagram of the whole apparatus:

Part D is the one that cost you a beer.
Next time, you'll pay attention in Antique Barbell Restoration 101A