Signed Rolex, Oyster Perpetual Date, Sea-Dweller, Submariner 2000, 2000ft=610m, Superlative Chronometer, Officially Certified, Double-Red model, ref. 1665, case no. 5’209’553, circa 1977

In very good overall condition, the present timepiece is a very rare and highly attractive example of the Sea-Dweller reference 1665, featuring a so-called Mark 4 or Mk4 dial, distinguished by the printing:

The "double red" colour is of a light red shade. Upon close inspection the printing appears to be made up of a series of dots, rather than direct brush strokes or application. The two double red lines show different sizes: the second line, "SUBMARINER 2000", is smaller than the first line "SEA-DWELLER".

The white characters of the depth rating on the Mk4 dial are both larger and of a different font than those found on earlier dials. In addition, the number 6 of the depth rating is closed. The Rolex crown is large, while the 5 tips and the large oval at the base of the crown are clearly defined.

Ref. 1665
Made for approximately 10 years from 1967 to 1977, the reference 1665 was the first timepiece designed for use in saturation diving. It was fitted with a Rolex patent gas escape valve in the band and guaranteed waterproof to 610 metres depth. The valve was first developed on the Submariner model and allows helium and other gases to escape, enabling the watch to stand compression.