Even More proving its mastery of chronographs and particularly substantial-frequency precision, ZENITH unveils the DEFY El Primero 21 by using a new El Primero calibre beating at a phenomenal fee of 50Hz for an accurate 1/one centesimal of the next chronograph perform. Inspired by British pilot’s watches with the seventies, https://www.watchesworld.com/understanding-the-complex-world-of-chronometers/