More Proving its mastery of chronographs and especially higher-frequency precision, ZENITH unveils the DEFY El Primero 21 using a new El Primero calibre beating in a phenomenal level of 50Hz for an accurate one/one hundredth of a next chronograph purpose. Now a long time given that its debut, TAG has https://www.watchesworld.com/understanding-the-complex-world-of-chronometers/