Someone thought long and hard about this design. It's simple, fits any size nut within a certain range, has two main stamped parts, and is durable. The Schulz's liked it (S. 343).
With great engineering like this, this wrench must have been intended for a military application - something like screwing in bomb fuses. Given the Nebraska location of the Schulz's and the Delaware location where I found it, I think it's provenance could have been the U. S. Air Force. What do you all think/know about this wrench?