Even Further proving its mastery of chronographs and specifically high-frequency precision, ZENITH unveils the DEFY El Primero 21 by using a new El Primero calibre beating at a phenomenal price of 50Hz for an accurate 1/one hundredth of a 2nd chronograph function. Thanks once more for choosing Watches World! We https://www.watchesworld.com/understanding-the-complex-world-of-chronometers/