Further Proving its mastery of chronographs and specifically high-frequency precision, ZENITH unveils the DEFY El Primero 21 having a new El Primero calibre beating at a phenomenal charge of 50Hz for an correct one/a hundredth of a next chronograph purpose. The Speedmaster gets the many adore in Omega’s chronograph lineup, https://www.watchesworld.com/understanding-the-complex-world-of-chronometers/