More Proving its mastery of chronographs and specially large-frequency precision, ZENITH unveils the DEFY El Primero 21 which has a new El Primero calibre beating in a phenomenal price of 50Hz for an correct 1/a centesimal of the next chronograph function. Now decades because its debut, TAG has Again returned https://www.watchesworld.com/understanding-the-complex-world-of-chronometers/