[ARC5] "ZA Impedance Adapter Mounting" parts

[Hubert Miller]

I have this tidbit: a 5 x 3 metal plate, black wrinkle, a mounting plate,
inscribed " IMPEDANCE ADAPTER MOUNTING ZA EQUIPMENT ".
Also, a small box which clamps to this base. The box is empty, has 4
~ 1/4 inch holes on front for controls; I think 2 holes were hacker
added; also 4 small holes on top where I think a nameplate was removed.
Still, this may have some value to some Navy avionics restorer. Mailed
free. 
BTW, what is a "ZA Impedance Adapter" ? 
-Hue Miller