Even More proving its mastery of chronographs and specifically large-frequency precision, ZENITH unveils the DEFY El Primero 21 that has a new El Primero calibre beating in a phenomenal charge of 50Hz for an precise 1/one hundredth of the second chronograph operate. My experience with the vendor, was truly good. https://www.watchesworld.com/understanding-the-complex-world-of-chronometers/