Calibre 2236 Is equipped with a Syloxi hairspring that is produced by Rolex and patented. This silicon hairspring provides a patented geometry that assures the calibre’s regularity in any situation. Additionally, all 3 watches benefit from a concealed attachment process that ensures seamless Visible continuity among the bracelet and case. https://www.watchesworld.com/understanding-the-complex-world-of-chronometers/