Even More proving its mastery of chronographs and especially higher-frequency precision, ZENITH unveils the DEFY El Primero 21 with a new El Primero calibre beating at a phenomenal amount of 50Hz for an accurate 1/100th of a second chronograph function. Equipment Patrol editors chose the Blancpain Air Command between their https://www.watchesworld.com/understanding-the-complex-world-of-chronometers/