single color that contrasted with the color of the main dial (i.e., both variants: a black dial with white sub-dials, and a white dial with black sub-dials), in contrast with Reference 6238, which retained a monotone scheme and a tachymeter within the crystal. However, rare "albino" variants of the Daytona are known to exist where sub-dial colors match the main dial like Reference 6238. The first known "Albino Daytona" was owned by Eric Clapton. The word "Daytona" was added below the 12 o'clock "Rolex Cosmograph" signature in 1964, then moved to a position above the 6 o'clock (hours) sub-dial by 1967. The first of the "exotic" dials (later named "Paul Newman" dials) were introduced in 1965. The Rolex Daytona was inspired by racecar drivers and enthusiasts, most notably, iconic actor Paul Newman, who reportedly wore his Daytona every day after he was gifted one by his wife. Newman typically wore it on a leather military strap, and was photographed wearing it in this fashion for the 1972 book Paul Newman - Les images d'une vie. The caseback bore a custom engraving: "DRIVE CAREFULLY ME". By 2005, Newman had replaced it with a Reference 6263 Daytona with a conventional dial, also a gift, bearing the inscription "DRIVE SLOWLY, JOANNE". The second Daytona was reportedly purchased in 1984, which prompted Newman to gift the first Daytona to his daughter's boyfriend, James Cox, that year. Second series This original series was in very short supply by the early 1990s, which led to a second series to meet demand, introduced in 1988 with Reference 16520. The second series uses a modified automatic winding movement, originally manufactured by Zenith for their "El Primero" watch, designated by Zenith as Calibre 3019PHC. The movement was originally designed in 1969 after development commenced in 1962 and remains the highest VPH (vibrations per hour) mass-produced chronograph movement on the market at 36,000 VPH. After Zenith was sold to the American company of the same name in 1971, the company discontinued production of mechanical movements in 1975. However, Charles Vermot, a senior engineer for Martel Watch Company (where the El Primero was made, and which had been acquired in 1959 by Zenith) had, over a period of months, secretly disassembled the tooling for the El Primero and stored it in the factory attic after the closure had been announced in 1975. After Zenith Radio resold Zenith in 1978, Ebel decided