18ct yellow gold, 40 mm Rolex Submariner oyster perpetual wristwatch. Model reference 16618. Blue dial with luminous dot hour markers and date aperture at 3 o'clock with cyclops lenssurrounded with a blue aluminium bezel. Powered by a 3135 Rolex movement. Significant features of this model are the trip lock crown, the rotating uni-directional bezel, and superlative chronometer with the 92908 flip lock, 18ct yellow gold oyster bracelet with extension link. Purchased in Switzerland some 20 years ago in St Gallen