It's a red LED laser pointer to be precise. Think Geek is selling a Star Trek, Original Series, officially licensed, "Phaser Laser Pointer" that will set your "corporate presentation skills to stun." The acrylic tip glows when the laser is on. For the geeks: Class IIIA laser, 640 nm wavelength, less than 5 milliwatts. Note, however, that it's smaller than it looks, keychain sized, and is only 4.4 inches long.
Check It Out: A Working Star Trek Hand Phaser