Even More proving its mastery of chronographs and precisely higher-frequency precision, ZENITH unveils the DEFY El Primero 21 by using a new El Primero calibre beating at a phenomenal price of 50Hz for an accurate one/100th of the next chronograph function. Chronographs — with their bezels, scales and sub-dials — https://www.watchesworld.com/understanding-the-complex-world-of-chronometers/