Even More proving its mastery of chronographs and particularly high-frequency precision, ZENITH unveils the DEFY El Primero 21 that has a new El Primero calibre beating at a phenomenal charge of 50Hz for an correct one/a centesimal of the second chronograph functionality. I'd happily use Watches World once more and https://www.watchesworld.com/understanding-the-complex-world-of-chronometers/