In 2017, Rolex celebrates the 50th anniversary of the Sea-Dweller, re-proposed in a new version that presents some substantial changes with small references to the original 1967 model. The brand's famous professional diver first of all enlarges the size of the case from 40 to 43 millimetres, while retaining the helium escape valve that has characterised it in all its evolutions. An absolute novelty is the presence of the Cyclope lens on the date window at 3 o'clock, present instead in many other Rolex models, for better reading of the date. On the black dial, as on the 1967 model, the red Sea-Dweller inscription returns. The Chromalight hour markers, coated with a long-lasting luminescent substance, are blue in colour and guarantee legibility down to a depth of 1,220 metres. On the mechanical side, the calibre 3235, already presented in 2005 but never before used on a professional model of the brand, is adopted. Its features include the Chronergy escapement, used on the new generation Rolex calibres. The steel Oyster bracelet is equipped with an Oysterlock safety clasp that prevents any accidental opening, with a double extension system that allows the watch to be worn over a wetsuit up to 7 mm thick.