Darth Vader Voice Changer Mask
As someone who spent a childhood playing Han Solo and Luke Skywalker in their quest to save the galaxy from Darth Vader and The Empire, having a fan around came in handy to mimic Vader's voice. Who knew someone would one day invent a $30 toy destined to eliminate the need for imaginative alternatives to the harmonic distortion provided by a spinning plastic blade encased in a metal grate. Of course, you also couldn't easily wear a fan attached to your head.
At that time, the Lucas licensing engine was content to collect money for comic books, action figures, lunch boxes, trading cards, bedding and apparel, not having ventured into the realm of custom Potato Heads and certainly not ready to release the secret voice-changing machine for a world wide audience in the form of a magical Darth Vader head.
The head and chest plate combination provides all the pitch bending and distortion required to make your voice sound like a lord of the Sith, as well as providing mechanically powered breathing noises and popular Darth Vader lines (in case you don't have them memorized already). 3 AA batteries is all it takes to join the dark side and embrace the vocal quirks of everybody's favorite sci-fi villain.