I recently purchased this airspeed/altitude indicator at an auction because I thought it looked interesting. It is made out of plywood and looks to be a mock up. There is a metal tag on it that says: Machine Gun Trainer Mark 2, The Vitarama Corp. Long Island City, NY. 1942. After some internet searches I found this link (The Waller Flexible Gunnery Trainer) describing the Waller Flexible Gunnery Trainer "one of the top secret developments of the war and was on the restricted list of equipment". "The Trainer was used by the U. S. Army Air Corps, U. S. Navy. and the British for the final training and retraining of machine gunners. It was declared "Essential to Winning the War". Preliminary training was obtained on less complicated and less accurate devices. It has been calculated that each trainer paid for itself over - two days of operation and thus saved many millions of dollars in war cost, plus the more important saving in men and planes which never can be properly estimated". I couldn't find any parts of the trainer for sale and am curious about its value. Any more info on this object would be appreciated.