Further More proving its mastery of chronographs and specifically significant-frequency precision, ZENITH unveils the DEFY El Primero 21 with a new El Primero calibre beating at a phenomenal amount of 50Hz for an correct one/one hundredth of a second chronograph operate. Complication: Refers to any look at movement further than https://www.watchesworld.com/understanding-the-complex-world-of-chronometers/