This Rolex reference 128348RBR is the Day-Date 36 in yellow gold, dressed with a gradient green-to-black dial, diamond hour markers and a diamond-set bezel. The Day-Date is Rolex's flagship, made only in gold or platinum and famous as the watch that first spelled the weekday out in full across the top of the dial — the model that earned the name "the President." The 36mm case here is the original proportion the Day-Date has worn since 1956, and in yellow gold with its factory diamond bezel and gem-set green dial it is the line at its most decorative. Driving it is the current-generation calibre 3255, a Superlative Chronometer automatic movement with around seventy hours of reserve. The 18k yellow gold Oyster case measures 36mm in height and width with a thickness of 12.1mm and is water resistant to 100m, the day shown at twelve and the date at three.