By Aston & Mander & Co. London. Stores reference 13/88. 1944 dated. 'Capt. Field's Improved' boxwood parallel rule with brass fittings. Approx. 45cm/18" in length x 7.5cm/3" wide when closed. Clear Air Ministry and crown markings. Some minor 'bumps' around the edges and tarnishing of metal parts. Also marked '49 NAV DEPT.' Very good used condition overall. As used by the Navigator for route plotting in bomber aircraft. Stock code M20393.