Like all Rolex watches, the Oyster Perpetual Datejust 31 is covered by the Superlative Chronometer certification redefined by Rolex in 2015. This designation testifies that every watch leaving the brand’s workshops has successfully undergone a series of tests conducted by Rolex in its own laboratories according to its own criteria, following the official certification of the movements by the Swiss Official Chronometer Testing Institute (COSC). These in-house certification tests apply 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 is of the order of −2 /+2 seconds per day – the rate deviation tolerated by the brand for a finished watch is significantly smaller than that accepted by COSC for official certification of the movement alone.

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.