Calibre 2236 Is equipped that has a Syloxi hairspring that is made by Rolex and patented. This silicon hairspring includes a patented geometry that makes sure the calibre’s regularity in almost any place. ZENITH launches the 135-Observatoire restricted version, making the acclaimed 135 calibre, serial winner on the international Chronometry https://www.watchesworld.com/understanding-the-complex-world-of-chronometers/