Even More proving its mastery of chronographs and exclusively significant-frequency precision, ZENITH unveils the DEFY El Primero 21 by using a new El Primero calibre beating in a phenomenal fee of 50Hz for an exact 1/one hundredth of a 2nd chronograph function. Gear Patrol editors chose the Blancpain Air Command https://www.watchesworld.com/understanding-the-complex-world-of-chronometers/