The Sea-Dweller is now one of the most appreciated Rolex timepieces, possibly because of its genesis as one of the ultimate tool watches, born out of true necessity and grown to become an iconic piece of watchmaking.The helium escape valve was developed because when working in helium-rich atmospheres, tiny helium molecules would seep through the crystal and rubber gaskets into the watch and create pressure once the diver had surfaced. This would usually result in the crystal popping off. The development of the valve was meant to prevent this issue by letting the gas escape. Today, it is well established that Rolex worked with a number of divers and organizations around the world to aide in the Sea-Dweller's development. For example, the scientists of the American underwater habitat, Tektite, wore such watches in 1969 and 1970, and the same is true for the scientists working the Sealab III project. The name Sea-Dweller itself is a direct nod to the fact that the model had been developed to meet the demands of scientists living - or “dwelling” - under the sea. Following the positive results obtained with these companies, Rolex went on to publicly commercialize the model.

The earliest iterations engraved with “Patent Pending Rolex Oyster Gas Escape Valve” on their casebacks (such as the present example) are highly sought after. These early models were practically prototypes, and their caseback are stamped to the inside with the last three digits of the watch’s serial number - “298” for the present example.

The overall condition of the watch is superb. The engraving to the back are very well preserved, to the point of even retaining some of the original black filling. The dial is simply breathtaking: devoid of marks or scratches, it showcases strong graphics with vibrant colors and no losses or fading. The star of the show might however be the luminous material, which has aged to a lovely sand tonality, granting the watch an incredible vintage appeal. Boosting such attractiveness with the intellectual appeal of a “Patent Pending” 1665, the present watch will elate any serious Rolex collector.