Calibre 2236 Is equipped using a Syloxi hairspring that is produced by Rolex and patented. This silicon hairspring features a patented geometry that ensures the calibre’s regularity in almost any situation. Tissot traces its extensive record again to 1853, when it was founded by the father-son team of Charles-Fileélicien Tissot https://www.watchesworld.com/understanding-the-complex-world-of-chronometers/