With The event of your ZENITH calibre, the Manufacture’s founder was nicely on his way to achieve his star: The creation of the trusted movement employing standardised manufacturing strategies. Declaring the winner of the race to develop the primary automatic chronograph in 1969 is contentious company, so Zenith’s “El Primero” https://www.watchesworld.com/understanding-the-complex-world-of-chronometers/