In celebration of the Daytona’s 25th anniversary, Rolex released its first self-winding chronograph model, the reference 16520, at Baselworld 1988. Technically impressive, it was powered by the automatic Zenith El Primero calibre, which was substantially modified by Rolex. Over the years, this milestone timepiece has become a collectors’ favorite, with grail examples such as the early and rare “R” series chronographs like the present watch.

Indeed, while reference 16520’s popularity has increased dramatically in the past years, few automatic Cosmograph Daytonas are as beloved as the first-generation models ‘R Series’. As opposed to later examples, the Cosmograph script sets further apart from the first four lines of text, as if floating in the middle of the dial. Of particular note is the “inverted 6” on the 6 o’clock subsidiary register, highly appreciated by collectors today. The reference 16520 was the first Daytona to be fitted with a sapphire crystal, and with a larger case diameter measuring 40 mm, which was equipped with the rare 200 graduation bezel. Later examples would have a bezel calibrated to 400 units.