In 1967 Rolex launched the Sea-Dweller, the first ever sports watch to feature the integration of a helium escape valve (HEV). This design allowed divers to dive deeper without worrying that the watch might fail. When initially released, Rolex was still working towards the patent for this new technology and the early Sea-Dwellers were engraved with the wording “Patent Pending Rolex Oyster Gas Escape Valve” on the case back. This Patent Pending reference 1665 is a very fine and early example. Dating from 1967, the dial is a Mark 2 (Mk2) type with the double red printed Sea-Dweller on the first line and Submariner 2000 on the second. The Mark 2 dial is identified by the long and skinny cornet with the letters “D” and “W” for the word “Sea-Dweller” almost touching. What is also very charming is the uniform way that the lumes and hands have aged consistently and the warm ivory tone they have become. Striking still, is the black finish of the dial that has started to turn a very subtle shade of brown that can be identified in certain lights. The inside case back is stamped IV.67 and the watch is fitted with an Oyster bracelet, with a rare “Pat Pend”-signed extension piece.
It is interesting to note that a very similar Double Red Sea-Dweller with patent pending case and mk2 dial bearing the case number 1’720’913 was sold at public auction in December, 2012. According to literature, only around 150 examples of these early examples were made with serial numbers ranging between 1.7 million and 2.2 million.