RAF Course & speed calculator MK.IIA
Dimensions:W: 13cm (5.1")H: 15cm (5.9")D: 2.5cm (1")
Stores Ref. 6B/125. By H.T.A (1928) Ltd. Metal construction with sliding section. Marked with scales for airspeed, drift and distance etc. Show use and wear but in very good overall condition. Used by Navigators to calculate flight routes. Stock code M21831.