Additional Proving its mastery of chronographs and particularly substantial-frequency precision, ZENITH unveils the DEFY El Primero 21 by using a new El Primero calibre beating in a phenomenal amount of 50Hz for an precise one/a hundredth of the next chronograph function. 1844: Adolphe Nicole introduces the reset function, enabling different https://www.watchesworld.com/understanding-the-complex-world-of-chronometers/