More Proving its mastery of chronographs and especially higher-frequency precision, ZENITH unveils the DEFY El Primero 21 that has a new El Primero calibre beating at a phenomenal rate of 50Hz for an accurate 1/one centesimal of a second chronograph operate. Declaring the winner of the race to construct the https://www.watchesworld.com/understanding-the-complex-world-of-chronometers/