Calibre 2236 Is equipped having a Syloxi hairspring that is produced by Rolex and patented. This silicon hairspring incorporates a patented geometry that ensures the calibre’s regularity in any placement. 6 miles, or 55.7 km) at the end of a six weeks’ voyage. (The geographical mile is defined as one https://www.watchesworld.com/understanding-the-complex-world-of-chronometers/