Driv-e-mocion is a nifty device that attaches to your rear window and can be programmed to display a variety of messages — in form of smiling/frowning faces or words. Best of all, it’s priced at just $20 here.
Given, the four letter words may anger the person behind you even more, it is still cool to put them in their place, geekily
[via Gizmodo]