WW1 Royal Naval Air Service Pilot's Wing Silver RNAS Engineer Propeller brooch

A superb original First World War period 'Royal Naval Air Service pin badge'; large eagle surmounted by blue enamel 'RNAS' title scroll and rare remaining additional Engineer's swing propeller below, the reverse impressed 'STERLING SILVER. Very good condition, complete with original pin fittings, no damage to the enamel.Wingspan approx 52mm.The Royal Naval Air Service 'RNAS' was the air arm of the Royal Navy during the First World War, it merged with the Royal Flying Corps on 1 April 1918 to form the Royal Air Force.