Sea Dweller Model 1665
This model has gained relative high popularity lately. As the price for this model with red writing has reached a price level of more than 20k US$ for an example without box and papers, the 1665 white model has received more and more interest. This has then again resulted in a price increase over a short period in the last year. Speculation on the number for Red 1665 contra the white 1665 has been a topic for discussion. Somehow the number of white 1665 could be lower than the number of red 1665 based on the years of availability. But this has little impact on the price, because as long as the red 1665 is more in demand - the price are not likely to drop at any time in the future.
What is so special about the Sea-dweller model 1665? It was the first real special dive watch made special for a specific purpose. The deep dive company COMEX in France was among the first to use saturated diving where the Nitrogen in the air is replaced by Helium - allowing deep diving to depths below the magic 60-70 meters that are the maximum with normal air. With the mixture of oxygen and helium the maximum depth could be extended many times.
But the use of helium caused a other problem for the divers that spend many hours in pressure chambers in order to allow the nitrogen to leave the body and not get diving sickness. When having spend some time in high pressure it happened that the tiny helium molecules slowly entered the watch building up the pressure. When decompressing the speed of which the helium molecules was to escape from the watch could sometime not keep up with the speed of the decompressing causing the higher pressure inside the watch to pop of the crystal making the watch useless (at least until it had a service). This let to the development of a helium escape valve in a standard Submariner that was used and tested by COMEX divers. As this was found to be a perfect solution to a major problem - Rolex introduced this feature in the sea-dweller and voila the Rolex 1665 Sea-dweller was born.
I feel that the 1665 sea-dweller (of cause a Double Red Sea-Dweller = DRSD) would be nice, but any 1665 is a must have for any Rolex collection of tool watches. I find it interesting that Rolex made these special modifications and release it as a normal of the shelf model for anyone to buy. This is the true meaning of the Rolex Tool Watch range, making a watch that in some way "solves" a problem related to a specific area. This is also the only Rolex watch that have engraving on the back as standard.
My second 1665 is from 1980 (from caseback) and serial 6,6 mill. and have the original T dial and T hands
Dial variations of the 1665 are many ranging from single red, double red, white, and new replacement dials. I will not start my own 1665 dial variation web page for now but link to http://www.doubleredseadweller.com/ that has some of the best information about dial variations on the 1665 sea-dweller and a must website to visit for any looking to buy any type of 1665 model.