old AIRCO combination wrench

Well OK...since folks seem to be into 'combination wrenches' today, here's the first item from the boxful of tools that followed me home from 'up north' recently. ;-) Until now this has been in my Dad's tool box as long as I can remember, but I have no earthly idea where he got it or why...?

Roughly 8-1/2" long, this wrench has 6 different 'sizes' from 7/16" to 1-1/8" plus a 3/8" square 'socket' type thing on one end. It has the name "AIRCO" in an oval logo on one side and number "8090028 MADE IN U.S.A." on the other.

I'm guessing, based on the name and that odd square fitting thing, that this wrench might have been meant to be used with pressurized air/gas tanks and equipment, such as those used for welding torches and similar things. Does anybody else know for sure, or differently??