Even Further proving its mastery of chronographs and specially high-frequency precision, ZENITH unveils the DEFY El Primero 21 having a new El Primero calibre beating in a phenomenal level of 50Hz for an precise 1/a hundredth of a 2nd chronograph purpose. Declaring the winner in the race to create the https://www.watchesworld.com/understanding-the-complex-world-of-chronometers/