[Milsurplus] Odd Wehrmacht earphone

[Hue Miller]

I found this odd (at least, new to me) type of 
German WW2 earphone and cannot guess 
what it was for.

It's about 1" diameter by 1/2" deep to the earphone
part. It does not have a headband, it has a behind-
the-ear wire quite like later early transistor radio
and portable tape recorder earpieces. The cord is
terminated in the usual German 2-banana type plug.
The earpiece back has the word IDEAL. Sounds 
like something that would have been supplied
with a Superex kit or maybe even an early Zenith
transistor radio - but it has a tiny Waffenamt 
eagle, acceptance stamp, the kind with swastika
carried by the eagle. I do not have a guess for what
it was for. Not spy radio, those used standard 
headphones. Unless, really wild guess, it was for
one of those hidden-in-the-clothing DF receivers
for tracking down spy transmitters. But that's 
really my guess and a wild one.
Input?
Tnx, Hue Miller