More Proving its mastery of chronographs and specially large-frequency precision, ZENITH unveils the DEFY El Primero 21 which has a new El Primero calibre beating in a phenomenal price of 50Hz for an accurate 1/one hundredth of a 2nd chronograph function. The Speedmaster receives all of the love in Omega’s https://www.watchesworld.com/understanding-the-complex-world-of-chronometers/