Further More proving its mastery of chronographs and precisely higher-frequency precision, ZENITH unveils the DEFY El Primero 21 which has a new El Primero calibre beating at a phenomenal charge of 50Hz for an precise one/one hundredth of a second chronograph purpose. Tudor’s Black Bay line is on fireplace with https://www.watchesworld.com/understanding-the-complex-world-of-chronometers/