Calibre 2236 Is fitted which has a Syloxi hairspring that is produced by Rolex and patented. This silicon hairspring has a patented geometry that guarantees the calibre’s regularity in almost any placement. Whether for personal gratification or being an investment decision, COSC-accredited watches distinguish them selves while in the world https://www.watchesworld.com/understanding-the-complex-world-of-chronometers/