Am I having deja vu? Weren’t we asked this before?
Yes, in October and I meant to reply but forgot.
I have a feeling it’s from The Fantastic Journey. The character Varian from the 23rd century had a sort of tuning fork which he used to focus his mental powers.
I’ll have to do some more research though since I’m not sure and may be muddling it with something else.
Edit – Nope, I’ve found a web page which backs me up
[url]http://www.tvacres.com/aliens_varian.htm[/url]
and here’s a page with a pretty picture
[url]http://epguides.com/FantasticJourney/[/url]