The Precision of a Rolex Superlative Chronometer is of the buy of −two/+2 seconds per day – the speed deviation tolerated through the brand name for just a completed watch is appreciably scaled-down than that recognized by COSC for official certification in the motion on your own. The Superlative Chronometer https://www.watchesworld.com/understanding-the-complex-world-of-chronometers/