Calibre 2236 Is equipped by using a Syloxi hairspring that is produced by Rolex and patented. This silicon hairspring contains a patented geometry that guarantees the calibre’s regularity in any place. 6 miles, or fifty five.seven km) at the end of a six weeks’ voyage. (The geographical mile is defined https://www.watchesworld.com/understanding-the-complex-world-of-chronometers/