Stores reference 13/88. By the lesser known manufacturer J.A Nicholl & Co. 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 wood loss/chips at the left corners and tarnishing of metal parts. Excellent used condition overall. As used by the Navigator for route plotting in bomber aircraft. Stock code M18083.