The Rolex Sea-Dweller reference 126603 is the first and only two-tone Sea-Dweller in the model's history, introduced at Baselworld 2019 as a complete departure from nearly five decades of all-steel professional dive watch tradition. The 43mm Oyster case combines Oystersteel with 18k yellow gold on the bezel, winding crown, and bracelet center links — what Rolex terms Yellow Rolesor — while preserving every credential that has defined the Sea-Dweller since its 1967 origin alongside professional saturation divers. Rated to 1,220 meters of water resistance, the case carries the helium escape valve that permits safe decompression after extended saturation, paired with the unidirectional 60-minute Cerachrom ceramic bezel finished with yellow gold numerals. The black lacquered dial is fitted with large Chromalight applied indices and Mercedes hands for instant low-light reading, while the Cyclops magnifier over the date window at three o'clock marks one of the most significant cosmetic departures in the Sea-Dweller line. Powered by the in-house Rolex Caliber 3235, a Superlative Chronometer with paramagnetic blue Parachrom hairspring, Chronergy escapement, Paraflex shock absorbers, and approximately 70 hours of power reserve. Worn on the matching Yellow Rolesor Oyster bracelet with Glidelock and Fliplock extension systems. 2025 production, pre-owned in excellent condition with full Rolex box and papers. Affirm financing available at checkout.