Calibre 2236 Is fitted having 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. Tissot traces its long historical past back to 1853, when it had been Established by the father-son group of Charles-Fileélicien https://www.watchesworld.com/understanding-the-complex-world-of-chronometers/