Further More proving its mastery of chronographs and specially large-frequency precision, ZENITH unveils the DEFY El Primero 21 that has a new El Primero calibre beating at a phenomenal charge of 50Hz for an accurate 1/a centesimal of a next chronograph perform. To advertise the art of watchmaking to as https://www.watchesworld.com/understanding-the-complex-world-of-chronometers/