Further Proving its mastery of chronographs and particularly significant-frequency precision, ZENITH unveils the DEFY El Primero 21 using a new El Primero calibre beating in a phenomenal amount of 50Hz for an precise 1/one hundredth of a 2nd chronograph function. Gear Patrol editors selected the Blancpain Air Command among their https://www.watchesworld.com/understanding-the-complex-world-of-chronometers/