Plotting Machine AN-5750 in Wooden Case

Here is an authentic WWII-era navigational plotter used by aircraft navigators to plan, plot, and track their course along a chart.  The plotter would be affixed to a navigator's map table and laid upon the map of the flight plan, typically in a large aircraft. 

The kit includes the plotter (a protractor with base), two lengths of straight edge, a two-piece mounting clamp, an extra tension band, and an envelope of fasteners.  

This example is in its original wooden case, measuring ~23 x 9 x 4 inches.