Rolex doesn’t mess with a winning formula, which is why it rarely updates models – so the new improved Sea-Dweller reference 126600 is a welcome surprise, especially coming a mere three years after the last iteration. The case has gained three millimeters in diameter from 40mm to 43mm and, most obviously (and controversially), now has a cyclops date window on the crystal. Inside, a new caliber 3235 movement is based on the 3255 first seen in 2015 in the Rolex Day-Date 40, yet this version boasts 14 new patents not on the 3135 in the 2014 Sea-Dweller. All this tinkering has resulted in a much better power reserve (up from 40 to 70 hours). One thing that thankfully remains unchanged is this diver’s water resistance: an impressive 1,220 meters. And, due to natural conditions at such depths, as the environment in which the new Sea-Dweller will be operating will be light-restricted, Rolex has added a corresponding increase is in Chromalight lume to go with that increased case size. Not only does Chromalight glow for eight hours, twice as long as SuperLuminova, the blue hue makes it easier to read during wreck dives or underwater cave exploration. It’s a neat trick to improve an iconic design, fortunately this is something Rolex continues to deftly accomplish – which is why this piece is deservedly one of Brogue’s favourite watches from 2017.