Even More proving its mastery of chronographs and precisely superior-frequency precision, ZENITH unveils the DEFY El Primero 21 using a new El Primero calibre beating in a phenomenal fee of 50Hz for an correct one/one hundredth of a 2nd chronograph operate. Chronographs — with their bezels, scales and sub-dials — https://www.watchesworld.com/understanding-the-complex-world-of-chronometers/