SIGNED ROLEX, SEA-DWELLER, SUBMARINER 2000, DOUBLE-RED MODEL, REF. 1665, CASE NO. 2'128'224, CIRCA 1969

The helium valve, allowing helium and other gases to escape hence enabling the watch to withstand compression even at extreme depths, was developed by Rolex in cooperation with the French diving firm COMEX and used for the Submariner references 5513 and 5514. Following the success of these models, Rolex decided to commercialise their invention with the launch of the celebrated Sea-Dweller reference 1665 in 1967, the first wristwatch designed for use in saturation diving, fitted with a Rolex patent valve in the band and guaranteed waterproof to 610 meters depth.

The model was rushed to production while Rolex had not received the final approval for the patent of the helium valve, resulting in the very first models of reference 1665 being sold with the case backs engraved (Patent Pending) in parenthesis. Very few examples of these early examples were made with serial numbers ranging between 1.7 million and 2.2 million.

The present reference 1665 is one of these extremely rare examples, featuring a number of specific characteristics of this celebrated version, clearly distinguishing them from their 'patented' successors:

- Most evidently the so-called Mark 2 dial, standing out by the long and skinny cornet with the letters 'D' and 'W' for the word 'Sea-Dweller' almost touching.

- 'Oyster Gas Escape Valve' and (Patent Pending) engraved around the case back.

- Inside case back stamped 1665, the last three digits of the serial number '224' and quarter and year of production 'IV.67'.