What is Relay crime and how to prevent it ?

This is how some technical person make some kind of device which operate as a fake key signal catcher and by this they can easily unlocked you car.
This happened in west midland where a Mercedes is been robbed by relay thefts.This video clearly represents that how the do it and how this device works. They don't even break any things like the door screen to unlocked just tap some buttons on the devices and it unlocks.
In this video we also provides you the authentic methods to prevent this happens to you. The Methods are very simple and you can easily follow these to kept your expensive and beautiful cars save.