Further Proving its mastery of chronographs and particularly significant-frequency precision, ZENITH unveils the DEFY El Primero 21 using a new El Primero calibre beating at a phenomenal rate of 50Hz for an correct 1/a hundredth of a 2nd chronograph functionality. Even though black-coated cases usually look smaller sized about the https://www.watchesworld.com/understanding-the-complex-world-of-chronometers/