The Precision of the Rolex Superlative Chronometer is on the buy of −two/+2 seconds each day – the speed deviation tolerated through the model for any concluded watch is appreciably smaller than that recognized by COSC for Formal certification of the movement by itself. The Superlative Chronometer status is symbolized https://www.watchesworld.com/understanding-the-complex-world-of-chronometers/