Even More proving its mastery of chronographs and precisely superior-frequency precision, ZENITH unveils the DEFY El Primero 21 that has a new El Primero calibre beating in a phenomenal rate of 50Hz for an precise one/a hundredth of the 2nd chronograph function. Gear Patrol editors selected the Blancpain Air Command https://www.watchesworld.com/understanding-the-complex-world-of-chronometers/