"The Rolex Sea-Dweller, ref. 126600 is for the intrepid, the explorers-in-residence. If you're deep enough underwater - setting oil pipelines or discovering animals with ""giant"" in the name - that you're having to breathe a mixture of helium and oxygen this watch will mark you as a professional. Depth rated to 1,220 meters or approximately 4,000 feet it's a serious piece of kit and the last one you'll ever need. Uncomplicated, singularly focused, this watch doesn't have options, it comes one way: 43mm brushed stainless case with matching Oyster bracelet, black ""maxi"" dial with Chromalight lumed hour markers and Mercedes hands, Rolex patented black Cerachrom ceramic bezel and date cyclops at 3. For a single pop of color ""Sea-Dweller"" in red at the 6 to acknowledge the original 1967 Sea-Dweller, ref. 1665. Created to celebrate the line's 50th Anniversary the 126600 was the talk of the 2017 Baselworld Fair among Rolex enthusiasts the world over - almost every authorized Rolex dealer in North America has a waiting list for this piece, and for good reason. It's not hyperbole to call the 126600 a specialist watch and on the technical side it's loaded for bear with the screw-down, Triplock crown - as would be expected on a watch this consequential - and it's the first (and only) Rolex tool watch to employ the exemplary new Rolex in-house automatic movement - caliber 3235 - which features the new Rolex Chronergy escapement. To date we've only seen this technology in the luxury Day-Date and Datejust models, so putting it in this watch was a nice move. One of the things that makes the 126600 so great is that is was purposely built to solve a rather significant issue at the time. In the mid-1960s the US Navy, Jacques Cousteau and the Compagnie Maritime d'Expertises (COMEX) company were all separately developing deep water saturation diving techniques when COMEX came to Rolex with a problem: accumulated helium at depth was causing the crystals of their Rolex Submariners to pop off during decompression, which obviously isn't acceptable. Rolex responded by developing and then fitting a one-way helium escape valve to a handful of COMEX Subs but instead of forever modifying the Submariner line Rolex just made a brand new watch for brand new professional needs, a la the Sea-Dweller. It had a beefier case, thicker crystal, greater depth capability, helium valve, etc, which has been its m.o. ever since. And this example is the best yet. Rolex has always been aspiration but this ref. 126600 is something different entirely. This is a tool watch that has professional capabilities beyond what most humans can actually use but because of its size and comfort on the wrist it's a suitable everyday piece for anyone. That said, what this watch excels at is making you feel like you can become the next oceanic explorer, the next deep-water archaeologist, the next pioneer - you feel optimistic because you're prepared. This is the watch you gift to your children when you tell them to go and explore the world. You can rest assured this watch won't let them down. "