Hi

I have a Heuer dating to the 40's which I was told was military and possibly issued to the Swiss military. It looks like a 406 from what I have managed to find from scouring the internet and I do recall many years ago seeing an identical watch one serial number away from this one but no idea where that was.
If you have any ideas on what the reference is and whether there is a recorded military connection I would be most grateful.
The watch is fitted with a Landeron 13 movement (No.400997) and the caseback is marked inside and out with S/No.49097 with the Etanche-Pare-Choc-Non Magnetic markings.

Thanks in advance and I can provide additional images if required (I can only see the facility to add one image to a post)