Further More proving its mastery of chronographs and exclusively significant-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 exact one/100th of the 2nd chronograph operate. To advertise the artwork of watchmaking to as many https://www.watchesworld.com/understanding-the-complex-world-of-chronometers/