Further More proving its mastery of chronographs and specifically large-frequency precision, ZENITH unveils the DEFY El Primero 21 which has a new El Primero calibre beating in a phenomenal amount of 50Hz for an correct 1/a hundredth of a 2nd chronograph purpose. Now many years since its debut, TAG has https://www.watchesworld.com/understanding-the-complex-world-of-chronometers/