Rolex Day-Date President 1803

Reference 1803 identifies the third generation of the Day-Date model, featuring a 36mm Oyster case with a fluted bezel. It had a notably long production run from approximately 1959 to 1978. Mechanically, the 1803 is defined by its non-quickset movement. It was initially powered by the Caliber 1555 (18,000 vph), which was subsequently upgraded c. 1965 to the higher-frequency Caliber 1556 (19,800 vph) for improved isochronism. A hacking seconds function was incorporated into the Cal. 1556 around 1972. The absence of a quickset mechanism requires both the day and date to be set by advancing the main handset. A primary technical feature of this reference is its “pie-pan” dial configuration and its use of a domed acrylic crystal.