In case you own a nice or reasonably expensive car and you’d like to keep it that way, it would be wise that you either invest in a garage, or a small metal box.

The garage part is obvious, really. It puts a locked door between your car and anybody who might be interested in stealing it. The metal box however serves a completely different purpose – it masks the signal sent out by your car’s key.

It’s that signal that’s eventually cloned via a signal amplifier, and subsequently sent to a transmitter positioned close to your car. Once that’s finished, the transmitter basically becomes the key and tricks your car into thinking the real key has been used.

This video is an unfortunate, yet perfect example of how easily and quietly a modern car can be stolen. The incident took place in the UK and it involves what looks like a new Mercedes-Benz C-Class saloon. It took roughly 10-seconds for the thieves to boost the key’s signal into their transmitter, and then another 10 seconds to switch places and take off with the car. Here’s what the owner of the Merc had to say:

“Had my car stolen last night. Anyone got keyless go make sure you double click the lock button or put keys in a metal box. Apparently this deactivates the key.”

He also mentioned that the thieves were able to deactivate the car’s GPS tracker, which means authorities could have a really hard time catching up to them.