It's looking like it most likely belongs to a company that made pumps and windmills around 1919 (so far the only date I have found them at, but no ideas how long they were around before and after that yet). I have no proof what so ever that the wrench belongs to that company, but all signs point that way and I wouldn't think the "Etter" name would be all that prevalent even then. Still trying to find out where this company was located.
Still around in 1937 and were located in Chambersburg PA. And as early as 1907, so far.