Even More proving its mastery of chronographs and precisely substantial-frequency precision, ZENITH unveils the DEFY El Primero 21 that has a new El Primero calibre beating at a phenomenal amount of 50Hz for an accurate one/a hundredth of the second chronograph functionality. Tudor’s Black Bay line is on fire with https://www.watchesworld.com/understanding-the-complex-world-of-chronometers/