The Rolex Sea-Dweller reference 126603 is the first and only two-tone Sea-Dweller in the model's history, a watch that broke nearly fifty years of all-steel tradition when it debuted at Baselworld 2019. Combining the deep-sea engineering pedigree of the Sea-Dweller line with the visual warmth of 18k yellow gold on the bezel, winding crown, and center bracelet links, the 126603 elevates the professional dive watch into precious-metal territory while preserving every functional credential. The 43mm Oyster case is built in Yellow Rolesor and rated to 1,220 meters of water resistance, equipped with the helium escape valve that allows the watch to safely decompress during saturation diving. The unidirectional rotatable bezel features a 60-minute graduated black Cerachrom ceramic insert with gold-finished numerals. The black lacquered dial carries large Chromalight applied indices and Mercedes hands, with the date at three magnified by the Cyclops lens — the first time a Cyclops appeared on a Sea-Dweller. Powered by the in-house Rolex Caliber 3235 with paramagnetic blue Parachrom hairspring, Chronergy escapement, Paraflex shock absorbers, 70 hours of power reserve, and Superlative Chronometer certification. Worn on the matching Yellow Rolesor Oyster bracelet with Glidelock and Fliplock extension systems. Pre-owned in excellent condition, full set. Affirm financing available at checkout.