Deep-Sea Engineering The Sea-Dweller is a professional dive watch designed for extreme underwater conditions. Developed in collaboration with deep-sea explorers, it features a helium escape valve and robust construction. A timepiece built to perform at depth while maintaining Rolexs signature precision. Classic Configuration This 40mm Rolex Sea-Dweller, reference 16600, features a black dial with luminous hour markers and a rotatable 60-minute bezel. Powered by the calibre 3135 automatic movement with a 48-hour power reserve, it is fitted with an Oyster bracelet and secured by an Easylink Oysterlock clasp.