Additional Proving its mastery of chronographs and specially substantial-frequency precision, ZENITH unveils the DEFY El Primero 21 with a new El Primero calibre beating at a phenomenal rate of 50Hz for an precise one/a centesimal of the next chronograph operate. Chronographs — with their bezels, scales and sub-dials — will https://www.watchesworld.com/understanding-the-complex-world-of-chronometers/