I hate to throw another wrench in the gears, but I think may be a Door Closer Adjustment Wrench. I have been looking around at work for an older one that looks similar, but no luck. I have posted a pic from an ebay listing. The wrench on the right is the one I am thinking of, and is stamped LCN, a manufacturer of door closers that has been around for a long time. The square hole is for the shaft that the arm connects to. (you need to rotate the shaft 90° to put tension on the arm, before you set the arm). The spanner end is for adjusting mainspring tension. The older, heavy duty closers had a flat nut, ( for adjusting mainspring tension) that was notched to receive the spanner.. There are closer arms that use hex and square head set screws, to hold the arm in place, or to adjust the arm. The wrenches were typically unmarked, and often lost, after the installation, but I will keep looking. Regards, Lou