Rolex 1665 Double Red SeaDweller MK4 . The dial is without any flaws , great patina and and the hands while original have aged a shade darker which is common.. The case is thick with even lugs and sharp crown guard recently back from polishing. The original insert has turned to a very cool blue hue. This particular example was produced in 1976 with 4 million serial as should be for an MK4 DRSD. Movement is running strong and keeping excellent time.