In 1967, Rolex, in collaboration with COMEX, would go on to introduce one of their most intentional driven watches, the Seadweller. At the time, COMEX was at the forefront of saturation diving, conducting some of the deepest and most demanding dives ever attempted. While Rolex had already established the Submariner, it simply wasn’t engineered to meet the extreme requirements COMEX demanded at greater depths.

A critical issue emerged during ascent. As divers returned to the surface, helium trapped inside the watch had no means of escape, causing pressure to build and, in many cases, forcing the crystal to fail. In response, Rolex developed the Helium Escape Valve (HEV), allowing gases to safely vent during decompression. The reference 1665 Double Red Sea-Dweller became the first commercialized model to incorporate this innovation, rated to a depth of 2,000 feet.

With the HEV developed and its patent submitted but Rolex had not received final approval yet, the early examples had their casebacks etched with a “Patent Pending” engraving. This special detail has coined these early examples the Patent Pending Double Red Seadwellers. These early pieces have taken on a distinct identity among collectors and remain some of the most desirable vintage sports models Rolex produced.

This present example is what is known to collectors as a Mk1, identifiable by its larger, uniform text across the dial, a feature that distinguish it from later variants. While the red script often fades to pink, a defect in the ink used, the presence of strong, vibrant red speaks to the exceptional preservation of the dial.

Originating from Canada, this premier example is one of finest examples I’ve handled. Complete with all its documents, I cannot emphasize enough how beautifully preserved, including its original crazed crystal, it remains. Falling within one of the known batches, the unaltered 2.12m serial case showcases all its original factory finish. The Mk1 dial is in outstanding condition, with evenly aged “eggshell” lume that matches perfectly across the dial and hands. What truly sets this piece apart, however, is the vividness of the red text, something rarely seen at on these Mk1 variants.

As expected on the earliest DRSD’s, the last 3 digits of the serial is correctly engraved on the interior of the caseback. Powered by a Caliber 1570 movement, the watch is dressed on its original Patent Pending 9315 / 285 bracelet. 

Built for extreme conditions and produced in limited numbers, early DRSD’s saw hard use, making well-preserved examples exceedingly scarce. Pieces like this, early, complete, and in such pristine original condition are very seldomly encountered.

(Item: INVDBV_LM98)