I'm a bit late to the party, but these 2 open ended Dasco wrenches piggy-backed their way into my garage in a vintage wrench lot I just purchased off of ebay. This thread is pretty much all I can find on them.
1 is 3/8 - 7/16 with 1723 on reverse
1 is 3/8 - 1/2 with 1723-A on reverse
Both...