Rolex Daytona. The original series, produced in small quantities from the early 1960s to the later 1980s, has a four-digits model or reference number, This original series eventually became iconic but in very short supply in the early 1990s, which led to a second series to meet demand. The second series has a six-digit reference number, The new six-digit Daytonas are certified, self-winding chronometers with chronograph functions. Rolex was, and remains today, a sponsor of the 24 Hours of Daytona race at the time.
