In a nice and somewhat heavy box, this appears to be a antenna matching network. IF my memory is good, this was used to eliminate ghosts by being used between the antenna and TV set for the off-air TV signals by connecting one side of the twin lead to terminals 1 & 2 and then the other side to terminals 2 &3. The knob was adjusted and the phase of the signal was altered in order to reduce or eliminate ghosting. Don't hold me to that, but I think that is the case. Anyway, this would perhaps make a good ham project or even a box for a project. It is actually a nice specimen for what it is and hard to find if you are a collector. Sold as-is as-found with no return.