1999 Rolex Daytona Zenith Black Dial Ref. 16520 A Series

The Black Zenith

The Reference 16520 was launched in 1988 as the first self-winding Daytona from Rolex. Because Rolex at that time wasn't able to master it themselves they introduced the watch with the Zenith Cal.4030 automatic movement. It was an upgraded version of the original El Primero Cal.400 with extensive modifications such as as a new escapement with a much larger, freely sprung balance and balance spring with Breguet overcoil to enhance accuracy. Further a reduction in the balance's oscillation rate from 36,000 beats per hour to 28,800 beats per hour for reducing service intervals. All in all Rolex removed about 50% of the original parts from the movement and replaced them with their own. The date function was simply removed. A Daytona never had a date and we think it will never have one. In line with the above changes to the movement there were more firsts. The 16520 now had a sapphire crystal and a larger 40mm case. With all modifications the new Daytona became much more contemporary and wearable given its technical properties. The example offered here is an A Series from 1999, just year before the reference was discontinued and the new 116520 with 100% in-house movement was launched in 2000. The dial is signed 'Swiss Made' indicating the use of Luminova luminous on dial and hands.Further the last two production years featured the SEL bracelet, a 78390A with solid end links.The beautiful black dial is flawless. The market for these has gone up upon strong demand and there are times we cannot get our hands on a nice example.