High Grade Movement Identification

[rodabod]

Does anyone have any ideas about this one?

It is around 23mm diameter. Stem set. 
 

Thanks. 
 

 

The two marks on the movement are the Geneva Seal. 

[grsnovi]

"Around" 23mm suggests that it's "around" 10.1959 ligne which is more likely 10 L or 10.5 L. Did you measure it with a caliper?

What is it sitting on? Is that the back side of the dial? What does the other side of the dial look like?

It would be helpful if you would remove the balance to see if there is a marker's mark under the balance (on the main plate).

I didn't see that keyless works configuration in BESTFIT.

[oldhippy]

Here is the I D in the red circle. 

[rodabod]

The two marks on the movement are the Geneva Seal. It is not a maker’s ID. There are no other marks on the movement, including under the balance cock.  
 

The main diameter of the movement is 22.9mm. 

The wider ring is a movement ring. On this ring mounts a dial which is a snap-on dial like you find on many high grade watches. No makers name including on the back of the dial. 
 

 

 

[oldhippy]

Then it has to be one of these makers. Cartier, Chopard, Roger Dubuis, Vacheron Constantin, Louis Vuitton and Ateliers deMonaco

[nickelsilver]

While I don't recall seeing one exactly like that, it is calling out LeCoultre to me (the setting parts look very LeCoultre). They supplied movements in ebauche or finished form to many different makers 100 years ago, from Patek to anonymous. Sometimes on an otherwise unmarked movement you will find a tiny stamped "LeCoultre" somewhere on the underside of the barrel bridge. Worth having a look.

[rodabod]

Thank you very much for the advice. Much appreciated.