ZENITH Solidifies its Worldwide status as being the primary manufacturer of precision chronometers and devices across quite a few domains. The 3rd major step happened from the early 1900’s. The shape from the timekeeping equipment transformed in favor of your wristwatch. The first chronometer wristwatch movement came in about 1910, https://www.watchesworld.com/understanding-the-complex-world-of-chronometers/