Rolex, one of the most popular and successful watch brands in the world, is known for one thing: STONE-COLD RELIABILITY. Even as the “Big Three” has spent that past hundred years harping on tradition, Rolex has been steadfast in producing some of the most solid tool watches ever made, PERIOD.

Just like the Rolex Sea-Dweller, which was introduced in 1967 and developed in conjunction with Comagnie Maritime d’Expertises (COMEX), a French commercial company specializing in deep-dive operations. It was waterproof to a depth of 610 meters (2,000 feet), more than triple that of the Submariner, and was Rolex’s next-generation “ultra-waterproof” professional diver’s watch.

To mark the 50th anniversary of the Sea-Dweller this year, Rolex has introduced their newest, and possibly, best Sea-Dweller yet

In the early 60s commercial diving had given way to the need for “saturated” diving, which allowed professional divers (such as the divers of COMEX) to reach hitherto unreachable depths. These prolonged deep dives necessitated that the divers use of an air mix that contained large percentages of helium.

But helium molecules are among the smallest in the world, and they permeate everything – even the inner part of a watchcase, which becomes saturated with helium as the pressure inside the case equalizes with the pressure inside the chamber during decompression. This is why deep-sea divers have often reported that the crystals of their watches pop out like champagne corks.

The Rolex-patented helium escape valve is essentially a one-way valve, which safely “vents” the helium trapped in the watch at a pre-set pressure level during decompression, and it does this without compromising the integral compact seal of the watch

The Rolex-patented helium escape valve solved this problem. Essentially a one-way valve, the escape valve safely “vents” the helium trapped in the watch at a pre-set pressure level during decompression, and it does this without compromising the integral compact seal of the watch.

To mark the 50th anniversary of the Sea-Dweller this year, Rolex has introduced their newest, and possibly, best Sea-Dweller yet, the Ref. 126600. Thickness remains at 15 mm, but at 43 mm in diameter, it’s definitely the biggest, the increase of which was designed to end all Submariner/Sea-Dweller comparisons from here on out. Thus, not only is the diameter larger, but so is everything else: larger bracelet, larger bezel, larger indexes, larger hands, and a welcome larger buckle.

(the larger diameter) is primarily designed to end all Submariner/Sea-Dweller comparisons from here on out

Otherwise, the Sea-Dweller retains the same depth rating 1,220 meters (4,000 feet) as the Sea-Dweller 4000 (ref. 16660) of 1978; a case and bracelet in 904L steel; a unidirectional rotatable bezel with a Cerachrom insert in ceramic; a Chromalight display with long-lasting luminescence; the patented Triplock winding crown with triple waterproofness system; an Oysterlock safety clasp; and the Rolex Glidelock and Fliplock extension systems, as well as the helium escape valve, the Sea-Dweller’s most renowned function. So, everything is business as usual, then…all except for three other things.

First: in a subtle nod to the model’s origins, Rolex has chosen to color the words SEA-DWELLER on the dial in red. So, not only is the brand acknowledging their past, they did it without having to create a Heritage Collection.

Second: the Cyclops date window, a point of contention for many purists because there has never been a Cyclops magnifier on any other Sea-Dweller to date. And that’s because the 120-bar pressure that the Sea-Dweller had to withstand was so high, the Cyclops magnifier would have simply broken from the crystal. Rolex has obviously solved this problem.

Last but not least is the next generation Calibre 3235 that powers the new Ref. 126600. Not only does the movement incorporate 90% new parts and new technologies, it is also being used for the first time to power the Sea-Dweller, making it the first watch of the professional collection to benefit from this new generation of movements.