Calibre 2236 Is equipped using a Syloxi hairspring that is made by Rolex and patented. This silicon hairspring incorporates a patented geometry that guarantees the calibre’s regularity in almost any posture. 6 miles, or fifty five.7 km) at the end of a six weeks’ voyage. (The geographical mile is defined https://www.watchesworld.com/understanding-the-complex-world-of-chronometers/