The Precision of the Rolex Superlative Chronometer is of the purchase of −two/+2 seconds on a daily basis – the speed deviation tolerated through the manufacturer for a concluded enjoy is considerably scaled-down than that acknowledged by COSC for Formal certification in the movement by yourself. The Superlative Chronometer status https://www.watchesworld.com/understanding-the-complex-world-of-chronometers/