For its instantly recognizable bracelet and the eminent figures that have worn it, the Day-Date has been known as the "presidents' watch", and the newest additions are set to carry on the name with high standards in quality and the redefined President bracelet that fits seamlessly into the Oyster case. The newly introduced perpetual self-winding 3255 caliber with 14 patents, entirely developed and manufactured by Rolex, sets new standards for precision, resistance to shock and magnetism, power reserve, reliability and ease of use. It features innovations such as the new and more efficient Chronergy escapement, the more resilient blue Parachrom spring in the oscillator, as well as the new-generation Perpetual rotor for more rapid winding. The 40mm 18K white gold Oyster case with bezel set with diamonds features scratch-resistant sapphire and Cyclops lens over the date aperture. With a screw-down case back and Twinlock double waterproofness system for the screw-down crown, it is water resistant to 100m. The watch is worn on the wrist with an 18K white gold President bracelet with semi-circular three-piece links and a concealed deployment Crownclasp. The black dial set with 10 baguette-cut diamonds features centre hands for hours, minutes and seconds, as well as instantaneous day and date in apertures.