Hi Guys
Is there any adjustment in the clasp on this watch? If not, what does the big block in the clasp do?

 

That's a wet-suit extension.

 

Try pulling the end link attached to "this bit" out toward you and see what's under the centre tongue.

 

Is there a trick to this?
I tried pulling the end link and no movement. I seem to remember when I bought the watch that I could get something to move, but not today

 

Ok, got it
Thanks for the help and there's an Omega vid

 

That's a great video...thanks for posting.