US Navy KM-2 Torpedo Camera Assessor by Abrams Instrument Equipment in original case. This device, a simple mechanical computer, was used by Avenger crews during World War Two. After programming in the target's speed, range and heading, as well as the aircraft's speed, altitude and target lead angle, a photograph was snapped at the moment of torpedo release so intelligence officers could later positively identify the target, check the pilot's technique and judge the results of the attack. Excellent.