Audemars Piguet Royal Oak Offshore Watch Titanium Gray 26420IO. Audemars Piguet’s Royal Oak Offshore highlights the grey and blue-toned octagonal dial contrast. The 43 mm titanium case is assembled with a ceramic bezel and a water resistance of 328 feet. This timepiece is powered by the self-winding 4401 calibre with a 50-hour power reserve.