Like All Rolex watches, the Oyster Perpetual Datejust 31 is roofed with the Superlative Chronometer certification redefined by Rolex in 2015. This designation testifies that every watch leaving the brand name’s workshops has correctly gone through a number of tests carried out by Rolex in its individual laboratories Based on https://www.watchesworld.com/11-of-the-best-womens-watches/