Further Proving its mastery of chronographs and precisely significant-frequency precision, ZENITH unveils the DEFY El Primero 21 by using a new El Primero calibre beating in a phenomenal charge of 50Hz for an accurate one/100th of a second chronograph functionality. Impressed by British pilot’s watches from your nineteen seventies, Hamilton’s https://www.watchesworld.com/understanding-the-complex-world-of-chronometers/