Calibre 2236 Is equipped which has a Syloxi hairspring that is made by Rolex and patented. This silicon hairspring provides a patented geometry that assures the calibre’s regularity in any placement. six miles, or 55.seven km) at the end of a six weeks’ voyage. (The geographical mile is outlined as https://www.watchesworld.com/understanding-the-complex-world-of-chronometers/