The Precision of the Rolex Superlative Chronometer is in the purchase of −two/+2 seconds each day – the speed deviation tolerated by the manufacturer for any finished watch is noticeably lesser than that recognized by COSC for Formal certification on the movement by yourself. The Superlative Chronometer position is symbolized https://www.watchesworld.com/understanding-the-complex-world-of-chronometers/