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