Calibre 2236 Is fitted having a Syloxi hairspring that is produced by Rolex and patented. This silicon hairspring includes a patented geometry that guarantees the calibre’s regularity in almost any position. six miles, or 55.seven km) at the end of a six months’ voyage. (The geographical mile is outlined as https://www.watchesworld.com/understanding-the-complex-world-of-chronometers/