Even Further proving its mastery of chronographs and particularly superior-frequency precision, ZENITH unveils the DEFY El Primero 21 using a new El Primero calibre beating in a phenomenal amount of 50Hz for an exact 1/one hundredth of a second chronograph functionality. Though black-coated situations often glimpse scaled-down over the wrist https://www.watchesworld.com/understanding-the-complex-world-of-chronometers/