Cosmograph Daytona Zenith Daytona 16520

First self-windingAutomaticA mechanical movement wound by a rotor as the watch moves on the wrist. Daytona, shown at Baselworld 1988, with the Zenith-based caliberCaliberThe designation of a watch movement, identifying its design or movement family. 4030. Grew to 40 mm, gained crown guards, a sapphire crystalSapphire crystalA watch glass made from transparent synthetic sapphire, valued for its resistance to scratching., applied markers, lacquered dials and “Oyster Perpetual” text. Steel throughout. Dials evolved through a series of Marks.