Further Proving its mastery of chronographs and especially significant-frequency precision, ZENITH unveils the DEFY El Primero 21 which has a new El Primero calibre beating at a phenomenal charge of 50Hz for an precise one/one hundredth of a next chronograph operate. Thanks all over again for choosing Watches World! We https://www.watchesworld.com/understanding-the-complex-world-of-chronometers/