S25 -Military Study Reel - RAF Short Stirling - naval aviation reel
British RAF Heavy Bomber
U.S. Naval Aviation Training Division
Military Study Reels consist of 7 different range and attitude (tilt/angle) images of a plane. These reels were issued to military personnel during World War II, for recognition and range estimation of both enemy and friendly aircraft.
Study Reels (S+Number) contain recognition of different angles of the same plane, while Test Reels (T+Number) test one's knowledge of recognition of different planes.
Condition:
 Reel:
excellent condition in plain unprinted sleeve