Just picked this one up. It is 34mm. I thought there would be a serial number on the movement but I only see it on the case back. Looking up the serial number I'm getting this from being about 1950? Any thoughts by anyone? Pretty cool little watch to me and the movement looks and seems to operate just fine. It was recently serviced and guaranteed for 2 years. My only complaint is that I was told it was 37mm but it is 34, however I kind of like it, and holds a 20mm strap with no problem although it looks more like 19mm between the lugs.