FCI Fairchild Camera & Instrument Army Air Force A10 Aircraft Sextant WWII era

  

This is a model A-10 aviation sextant by FCI, Fairchild Camera & Instrument Corp. It is a WWII era aviation navigational device used by the US Army Air Force. It comes in the original box and has the various parts as shown. I don't know what parts are missing, but there are some empty spaces in the box.