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