Even More proving its mastery of chronographs and precisely high-frequency precision, ZENITH unveils the DEFY El Primero 21 by using a new El Primero calibre beating at a phenomenal charge of 50Hz for an correct one/a centesimal of the second chronograph functionality. Our specialist reviewers spend several hours tests and https://www.watchesworld.com/understanding-the-complex-world-of-chronometers/