Even Further proving its mastery of chronographs and precisely large-frequency precision, ZENITH unveils the DEFY El Primero 21 with a new El Primero calibre beating in a phenomenal fee of 50Hz for an correct one/one hundredth of the next chronograph function. The term “chronometer” took on a slightly broader this https://www.watchesworld.com/understanding-the-complex-world-of-chronometers/