Further Proving its mastery of chronographs and particularly high-frequency precision, ZENITH unveils the DEFY El Primero 21 having a new El Primero calibre beating in a phenomenal fee of 50Hz for an accurate 1/a hundredth of a second chronograph functionality. When you purchase via one-way links on our web-site, we https://www.watchesworld.com/understanding-the-complex-world-of-chronometers/