Type D. Stores ref. 14B/746. Used by photo-reconnaisance staff to view aerial photographs for interpretation purposes. The use of these helped to acertain accuracy of bombing, pinpointing targets and so on. The viewer is in two sections - the main body has twin lenses set in flat metal plate with pivoting legs either side. These fit into a base plate, with notches on the legs permitting height adjustment. Air Ministry crown marked. Very good condition with just normal use and wear. Complete with the original fabric case of issue in good order. Stock code M21133.