Royal Oak 18K Yellow Gold Day-Date Moonphase 25594BA. Royal Oak Perpetual Calendar. PreOwned Light Showcase wear. Box, Papers were misplaced; we will include a certified appraisal with the matching serial number. Archive Papers Can be Ordered on request. Diamonds East Intl Boca Raton Fl. 4251 North Federal Highway 33431. Date, Month, Perpetual calendar.