Bass tuner maybe. It has an odd pattern along both sides that's pretty cool. Is there any way to tell it's age? Or maybe it's a tuner for a honkin' big mandolin.
Creskol, I believe you're right. I found a mandolin tuner in some of my old guitar parts and it's a close match size wise. And I realized that bass tuner knobs need more spacing than what this has. Now all I have to do is find the other tuner and the tail piece.