Ap diver internal bezel question

[Shauz]

Hello fellow trf's members looking at a few options as my next purchase (roo, ro and diver) just wondering how does the diver internal bezel works ? Does it have any locking mechanism ? Can you turn it while diving ? Do you unscrew it before you turn it ? Because I have a very old enicar Sherpa watch the have an internal bezel for gmt and I kinda disliked how it works could someone please elaborate for me ? Manythanks