The precision of each movement – formally Accredited to be a chronometer with the Swiss Official Chronometer Testing Institute (COSC) – is tested a next time by Rolex just after currently being cased, to ensure that it meets conditions which are considerably stricter than those of your Formal certification. https://sectordirectory.com/listings636852/how-to-identify-different-watch-hand-shapes-and-proportions-no-further-a-mystery