Further More proving its mastery of chronographs and exclusively high-frequency precision, ZENITH unveils the DEFY El Primero 21 which has a new El Primero calibre beating at a phenomenal level of 50Hz for an accurate one/a hundredth of a second chronograph functionality. To promote the artwork of watchmaking to as https://www.watchesworld.com/understanding-the-complex-world-of-chronometers/