Calibre 2236 Is fitted by using a Syloxi hairspring that is produced by Rolex and patented. This silicon hairspring includes a patented geometry that guarantees the calibre’s regularity in any situation. Lange & Söhne. I’ll explain why: the German model stepped on to the chronograph stage with their Considerably-praised Datograph https://www.watchesworld.com/understanding-the-complex-world-of-chronometers/