Calibre 2236 Is equipped with a Syloxi hairspring that is produced by Rolex and patented. This silicon hairspring incorporates a patented geometry that makes sure the calibre’s regularity in any posture. Tissot traces its extended background again to 1853, when it was Launched by The daddy-son crew of Charles-Félicien Tissot https://www.watchesworld.com/understanding-the-complex-world-of-chronometers/