The Precision of a Rolex Superlative Chronometer is on the purchase of −2/+2 seconds per day – the rate deviation tolerated because of the brand name for a concluded view is substantially scaled-down than that acknowledged by COSC for Formal certification from the movement on your own. The Superlative Chronometer https://www.watchesworld.com/understanding-the-complex-world-of-chronometers/