Even 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 correct 1/one centesimal of the 2nd chronograph purpose. Tudor’s Black Bay line is on fireplace with https://www.watchesworld.com/understanding-the-complex-world-of-chronometers/