Hello, I have a question about Omega's "pocket".

What is the professional name of this screw cap, is it a standard closure or protection?

What is it for, whether it was protection for the more working Omegs, I also met with the indication that it was a military omega.

 

I think the answer to your question (as I interpreted it) is that this style of case is called a “swing ring” case. There is only a front cover, and no removable case back.

 

And do you know what it was used for? Is it just an ornament?

 

I think it is a a first example of a waterproof case, similar to FB cases

 

I think @bubba48 is on the right track.

Let me see if I can remember where I saw something like this.

 

Possibly a variation of an "Explorerer's Watch", where the body was a swing ring case as @Canuck noted, and the crown was protected by a cap.

There is an article on David Boettcher's excellent web site.

Have a read.

https://www.vintagewatchstraps.com/waterproof.php

 

JimInOz, thank you for link. So this is the so-called explorer's watch. And the idea for the twisted crown is the work of Fitch from the late 19th century. Did I understand correctly?
Or maybe you still know what the symbols M, 22, U mean? These are not typical British or Swiss markings.
I apologize for my English but I am assisting with Google translator...