WW2 era U.S. Navy War Factory MK V Binocular Collimator with 5 ft. Lens

I happened upon an ultra rare item at a yard sale. A WW2 era U.S. Navy Mark V Binocular Collimator. The metal identification plate states; "U.S. Naval Gun Factory / W.N.Y. / Binocular Collimator / MK 5 / Serial # 108 / 1943, as pictured. Any help that you could give, "dumbed down", would be helpful. How was this thing used? There is not even any auction history to be found. The only references I could find for this item is as follows:
A statement from a prominent Binocular optics corporation; "Oberwerk has always been proud to say we’re the only binocular retailer on the planet (that we know of) with an in-house collimator". They actually have two, but one was reproduced. I called, but it was not for sale. In a historical research I found this; "During the early days of WWII, the US military—the mover and shaker of which was the Navy—moved from the British Mk I binocular collimation devices and conditional alignment to the 3-axis clinical collimation that, taking the axle into consideration, would allow the binocular to collimated at every position of the IPD. By 1941, the British recognized their Mk I collimator was very limited and determined it to be “obsolete.” The US experimented with a number of devices to accomplish this. The US Navy used the Mk 5 and the image projecting Mk 13 collimator while the British used the MK II, III, and IV which were much more problematic than the US Navy’s Mk 5, but more mobile.