More Proving its mastery of chronographs and particularly significant-frequency precision, ZENITH unveils the DEFY El Primero 21 using a new El Primero calibre beating in a phenomenal fee of 50Hz for an precise 1/one hundredth of a next chronograph operate. The term “chronometer” took on a rather broader that means https://www.watchesworld.com/understanding-the-complex-world-of-chronometers/