In the 1960s, the most used and trusted chronograph movement of industrial production was VALJOUX, which had varying levels of quality. Staying with the company’s philosophy and standards, Rolex chose the highest level of the movement available for its chronographs, in this case for its Daytonas.

Main characteristics of the Daytona chronographs calibers (calibers derived from the caliber 72 A):

• caliber engraving on the plate on the hub sinking of the balance wheel
• brand and jewels engraving on the chronographic bridge, in two versions:
  • in two lines (earlier models)
    • ROLEX GENEVE
    • 17 RUBIS
  • in five lines (more recent models):
    • MONTRES ROLEX S.A.
    • GENEVA SWISS
    • ADJ. TO 3 THREE POSITIONS
    • SEVENTEEN
    • 17 JEWELS
• place of manufacturing engraving on the train wheel bridge:
  • SWISS MADE FABR. SUISSE
• name brande engraving on the plate under the dial:
  • ROLEX GENEVE