Calibre 2236 Is equipped having a Syloxi hairspring that is produced by Rolex and patented. This silicon hairspring features a patented geometry that makes certain the calibre’s regularity in any position. Tissot traces its long record again to 1853, when it was Started by the father-son crew of Charles-Fileélicien Tissot https://www.watchesworld.com/understanding-the-complex-world-of-chronometers/