Okay I found a 125 Hz tuning fork, in some army engineer kit. I know this fourm isn't exactly for this topic, but I figure its closest to it. I'm curious what is it used for?

Any practical use of it?

I also am now curious... It has no significance musically.

They use it to eat with.

You hit it on something and use the sound as a references to tune something else.

It was probably used for some sort of calibration of an instrument, possibly radar or another precision system.