More Proving its mastery of chronographs and especially substantial-frequency precision, ZENITH unveils the DEFY El Primero 21 with a new El Primero calibre beating at a phenomenal fee of 50Hz for an accurate 1/a centesimal of a 2nd chronograph function. The Speedmaster will get all of the love in Omega’s https://www.watchesworld.com/understanding-the-complex-world-of-chronometers/