Authentic men’s WW2 era Rolex wristwatch with black radar dial.
 
The back bezel with ¼ century inscription and date 1917.  Believed to have started indicating a watch date of c1942.
 
I have to admit; when I first bought this watch the inscription on the back confused me quite a bit.
It was dated 1917 in yet the watch was clearly made a couple of decades later. It was then that I figured out that it had been awarded for 25 years of service, which had started in 1917. 

It is in extraordinary shape. I did have it serviced and it runs beautifully.

In my research, I have found very few of these in period with the complication. While it seems clear it was presented in 1941 the manufacture date could have been 39 or 40.

Great original and I doubt I will find another like it in the near future. 

Cheers, 
David Charles Grainger