Rolex Day-DateIn 1956, Rolex introduced one the most iconic watches ever made: the Day-Date. The Day-Date was the first waterproof self-winding chronometer certified wristwatch with a day and date function. And to top it off, it was only available in gold or platinum! Rolex also designed a new three-link bracelet, known as the ‘President,’ to pair with this special watch. With exception of the most modern executions, the Day-Date comes exclusively in a 36mm case.REF. 180xx1977 is the year of innovation in the history of the Day-Date. Rolex improved the guaranteed waterproof to a depth of 100 meters. There was a transition from the Plexiglas crystal to sapphire mineral crystal. The new caliber 3055 was introduced and of course the change from four to five digits reference.