Calibre 2236 Is fitted with a Syloxi hairspring that is made by Rolex and patented. This silicon hairspring has a patented geometry that guarantees the calibre’s regularity in almost any placement. Together with his colleague Thomas Earnshaw, the pair would produce simplified and realistic marine chronometers. The TAG Heuer Monaco: https://www.watchesworld.com/understanding-the-complex-world-of-chronometers/