롤렉스가 전 제품의 COSC기준을 상향 적용하여 인증한다고 합니다. etc

"The Explorer is covered by the Superlative Chronometer certification redefined by Rolex in 2015. This exclusive designation testifies that the watch has successfully undergone a series of tests conducted by Rolex in its own laboratories according to its own criteria, which exceed watchmaking norms and standards. The certification applies to the fully assembled watch, after casing the movement, guaranteeing superlative performance on the wrist in terms of precision, power reserve, waterproofness and self-winding. The precision of a Rolex Superlative Chronometer after casing is of the order of −2/+2 seconds per day, or more than twice that required of an official chronometer. The Superlative Chronometer status is symbolized by the green seal that comes with every Rolex watch and is coupled with an international five-year guarantee."