The Precision of the Rolex Superlative Chronometer is with the order of −2/+2 seconds on a daily basis – the speed deviation tolerated via the brand name for any finished look at is noticeably lesser than that approved by COSC for Formal certification on the motion alone. The Superlative Chronometer https://www.watchesworld.com/understanding-the-complex-world-of-chronometers/