<VV> strange valve/switch (no Corvair)

[Shaun]

I was digging through some parts and found an odd part:
It's a pushbutton switch with a round black button dished for your finger and two nuts on it for mounting through a dash panel, but instead of electrical, has vacuum hose attachments. I blew into it and it held pressure until I pressed the button, then it blew right through.
Does anyone know what the application might be? Air horn?

yea, non-Vairily ... Shaun