Further Proving its mastery of chronographs and exclusively significant-frequency precision, ZENITH unveils the DEFY El Primero 21 using a new El Primero calibre beating in a phenomenal charge of 50Hz for an precise one/a hundredth of the next chronograph purpose. Chopard's Mille Miglia collection celebrates the world's most stunning race. https://www.watchesworld.com/understanding-the-complex-world-of-chronometers/