FF and his Rolex GMT Master 2

We had dinner with FF and his wife Mon. FF was sporting his Rolex GMT Master 2 with a black bezel. Traditionally, the GMT is more commonly seen with a Red/Blue or Red/Black Bezel. As can be seen, the black bezel GMT it looks exactly the same as its Rolex cousins, the Submariner, and sometimes mistaken as such. The difference between a GMT and the Submariner lies in the extra hour time zone (for a second time zone), a 24 hour bi directional bezel (opposed to a 60 minute incremental uni directional bezel) and the difference in water resistance (Submariner being 300m compared to the GMT's 100m). Either Rolex watch are what I consider the ubiquitous sports watch.