Even More proving its mastery of chronographs and precisely substantial-frequency precision, ZENITH unveils the DEFY El Primero 21 having a new El Primero calibre beating at a phenomenal level of 50Hz for an correct one/one centesimal of the next chronograph functionality. Now a long time given that its debut, TAG https://www.watchesworld.com/understanding-the-complex-world-of-chronometers/