I picked this wrench up a while back online, no sizes marked but one end is .580 (14.7mm), the other .520" (13.2mm). Forged on one side is the name and city; it appeared to be Gacan Forge- Welland Ont., a manufacturer we've never heard of. On the other side is Forged Steel Treated. Another little mystery wrench, we thought!
Update; a couple of people corrected us on this one, much appreciated! It's actually a G4 Canforge wrench, a not uncommon name around here. We covered this manufacturer here.
Below, another Canforge wrench, this one has the name stamped into the head, leaving us to guess what size it is, I guess.