Prof Von Rook's De-Obfuscation Device

[Professor Von Rook]

This device emits a full spectrum beam, that when encountering any supernatural creature disguised as a human, will cause them to temporarily be seen for what they are.  The beam may be fired once every thirty seconds, and the shot is sustained for up to six seconds...Allowing you to draw the shot across a small gathering.   Normal folks appear unaffected...for the most part...Some have reported splotchy eyes...But, they may not be all together human so...We threw those out.  Anyway...  Here you are:

[Drew P]

ok-what's the watch-thang do and is that a valve stem for a tire I see?

[Professor Von Rook]

Excellent questions:  What does the watch-thang do? 
Answer:  It sustains the six second shot.

Is that a valve stem for a tire you see?
Answer:  Yes.