One of my former customers who is now in the same long-term care facility as my mom told me he bought this watch in the early ‘50s as a young man. Diameter is 34.5 mm and lume is poor, as could be expected at that age. It has been running fast and the power reserve is less than 24 hours, so the most likely possibility was that it had become magnetized. Testing it against my compass confirmed that today, so off to the watchmaker it goes.
The caseback is completely blank so there is no indication at all of water resistance. The owner thinks that it may have been magnetized when he visited a nuclear power station near the end of his career. I don’t know enough about nuclear power plants to know if that makes sense but @UnholiestJedi had a post about that very recently.
Semi-retired with a thrifty streak.