The Precision of a Rolex Superlative Chronometer is in the order of −two/+2 seconds each day – the rate deviation tolerated through the brand name for your concluded check out is substantially scaled-down than that accepted by COSC for Formal certification with the motion by itself. The Superlative Chronometer status https://www.watchesworld.com/understanding-the-complex-world-of-chronometers/