What is Sea Dweller MarkIII & Mark4?

[116520]

Since one of bro posted a Double Red Seadweller here, I was interested and went search in the web and found a few Double Red Seadweller listed in ebay. The question is how come there are SD classified as "Rolex 1665 Mark III Double Red Seadweller" and "Sea Dweller 1665 double red Mk4 dial "?

What is MarkIII and Mark4?

Thank you bros here....

[116520]

Nobody knows the answer?

[keltzar]

Dial variations for the early sea-dweller 1665.

[116520]

May I know what are the variations/differences between different mark versions?

Dial variations for the early sea-dweller 1665.