Rolex

Launched in 1967, the celebrated Sea-Dweller reference 1665 was the first wristwatch designed for use in saturation diving. The firm fitted the model with a gas escape valve and guaranteed waterproof to 610 meters depth. The valve was first developed on the Submariner model and allows helium and other gases to escape, enabling the watch to withstand compression during saturation diving. 

On the dial, two lines of text were printed in red: The Sea-Dweller text, and below, Submariner 2000, thus giving the watch its nick name, the “Double Red” or ‘DRSD”. Like the Submariner, it has a date window at 3, but it does not feature the cyclopes on the plexiglass. Another quirk of the Ref 1665 is that due to its specific waterproof specifications, the case back is stamped with the serial number to prevent it being swapped out in service. In early examples, it was just the last three digits of the serial, while later ones had the full serial engraved. 

The present watch has a MK4 dial, which is the final version of the original dials. It can be differentiated by its slightly heavier print for both the red and white text, which when viewed upon close inspection looks like it’s made up of dots. Additionally, the coronet has broader spikes and the ‘O’ under the coronet has a more pronounced opening.