Even More proving its mastery of chronographs and precisely high-frequency precision, ZENITH unveils the DEFY El Primero 21 which has a new El Primero calibre beating at a phenomenal amount of 50Hz for an exact 1/one centesimal of a next chronograph purpose. Gear Patrol editors selected the Blancpain Air Command https://www.watchesworld.com/understanding-the-complex-world-of-chronometers/