Omega manual waterproof - what year and likely caliber?
What a great site.
I've inherited an Omega from my grand father. It's a manual wind, stainless steel case, two-tone dial, small second hand. It's stated "waterproof" on the case back. I've had it serviced and oiled and it runs perfectly.
I don't want to open the case back myself of fear of damaging something.
Can you tell anyway when it's from and it's likely caliber?
I guess it's a "pre-Seamaster" and from around 1950's, but am unusure.