Calibre 2236 Is fitted by using a Syloxi hairspring that is made by Rolex and patented. This silicon hairspring contains a patented geometry that guarantees the calibre’s regularity in any posture. There you may have it, 5 brands that have played a massive role in the event on the chronograph. https://www.watchesworld.com/understanding-the-complex-world-of-chronometers/