The Precision of the Rolex Superlative Chronometer is on the order of −2/+2 seconds daily – the speed deviation tolerated via the brand name for the concluded look at is substantially scaled-down than that acknowledged by COSC for Formal certification of the movement on your own. The Superlative Chronometer position https://www.watchesworld.com/understanding-the-complex-world-of-chronometers/