A military issue OBSERVER wrist compass as used by Pilots, Royal Navy Clearance divers and the  Special Boat Servive (SBS). Military issue brass case with liquid filled compass and leather strap. Stamped to the case with 'PATT 261' and 'No 436B/53' and dating to around the 1950's. Angled magnifying prism mirror. Diameter 6.3cm x 3.2cm high. Sometimes these were fitted with a lanyard which divers hung off their equipment or also fitted to a swim board worn around the neck with a depth gauge and the highly collectable Rolex watch. This one has a longer strap which suggests it was worn around the thigh aswell as the wrist.
Weighs 260 grams