Unknown optics - Sight?

I found this in my dad's estate. I think it may be part of a sight (bomber? Tank?). Dad had a machine shop and transit/level repair business near Cleveland. I believe he did some work on military sights around the time of the Korean conflict (War). The Cadilac tank plant was nearby. Both parts have a high magnification elbow telescope with a 90 degree prism. Each has a focus knob and eye focus correction adjustment. They join together as shown but are too close to be able to look into both at once. The color suggests Army use. Can anyone tell me what this is?