ROLEX COSMOGRAPH DAYTONA 1991
Rare Rolex Oyster Perpetual Cosmograph Daytona 16520 from 1991. N series. Rare original Mk3 tritium inverted six dial. Original Mk3 steel bezel is in great condition. Steel case is like new. The watch is diving proof, tested at +10/-0.7bar. Zenith El Primero automatic chronograph cal.4030 movement modified by Rolex. Movement has been fully renoveted in January 2020.
Ref. 78360/503 steel bracelet original to this Daytona model. This bracelet was used in Daytona models only between 1987 and 1991. The watch comes with an original Rolex 16520 watch box and Longitudis warranty certificate. No original documents. The diameter of the case is 40 mm.
The watch has a 12-month service guarantee.
Rolex introduced the Daytona Cosmograph 16520 model in 1987. This model replaced the previous 37 mm ref. 6265 model with a Valjoux movement. Rolex chose the El Primero automatic chronograph movement cal. 3019PCH developed by Zenith as the movement for the new model. Introduced in 1969, it was the world’s first automatic chronograph movement and very advanced in design. Rolex did not adopt it as such, however, but made several changes to it. With changes to the movement’s timekeeping mechanism and wheel train, the frequency of the movement was reduced from the original 36,000 bph (beats per hour) to a frequency of 28,800 bph. This change resulted in a longer power reserve and a more maintenance-friendly design. The crystal in the 16520 models was sapphire, and the case diameter was 40 mm. This Daytona model remained in production until 2000, when Rolex introduced its first own chronograph movement, the cal. 4130.
The Mk3 dial on this watch is original and exquisite. There are small marks on the dial near the center of the small counter hands. The marks are only visible when viewed at high magnification.