The Precision of a Rolex Superlative Chronometer is with the purchase of −2/+2 seconds every day – the rate deviation tolerated from the brand name for the completed view is noticeably lesser than that accepted by COSC for Formal certification in the movement on your own. The Superlative Chronometer position https://www.watchesworld.com/understanding-the-complex-world-of-chronometers/