Additional Proving its mastery of chronographs and especially higher-frequency precision, ZENITH unveils the DEFY El Primero 21 by using a new El Primero calibre beating in a phenomenal level of 50Hz for an correct 1/a hundredth of the 2nd chronograph purpose. The Speedmaster receives many of the like in Omega’s https://www.watchesworld.com/understanding-the-complex-world-of-chronometers/