Help me identify impedance adapter?

[thebentern]

Hey head-fiers. I was digging into my boneyard of electronic parts and components when I came across this guy. I figured there was some kind of circuit inside the plastic cover so I opened it up. It appears to be some kind of an impedance adapter or something similar. I plugged in a pair of 32ohm earbuds and put it on the multimeter. It started out reading around 122ohm and dropped steadily to around 64ohm. So that leads me to a few questions.
Is this in fact an impedance adapter?
What are the two metal box components? (They almost appear to be adjustable with a flathead screw driver. Though I have not attempted this)
I'm guessing this could have come from a specific device. Does anybody have any idea of what that may be?

Here is a close-up of the circuit

Thanks