Photo shamelessly stolen from google images:



It's a little 2 button key pad you have to put a code into everytime you start the car or open a door.
So if you get dragged out of it or even if someone has the keys they wont beable to drive it, well not for very long you get 30 seconds to put the code in and if you don't it kills the engine locks all the doors and sets the alarm off.
Rich