Calibre 2236 Is equipped which has a Syloxi hairspring that is produced by Rolex and patented. This silicon hairspring has a patented geometry that assures the calibre’s regularity in any posture. Tissot traces its long history again to 1853, when it was Launched by the father-son team of Charles-Félicien Tissot https://www.watchesworld.com/understanding-the-complex-world-of-chronometers/