As Paddy says, it is a tracker used by fleet companies. I have one in my ALD lease car. Very useful for me, but won't give you any beneift at all if you're a private second-hand owner. It records all trips made in the car, recording times, mileage and location (based on the local telephone code). I then use this to note which are private and business trips on the Profleet website. I have found that on previous cars it has been left activated. I've been able to see where my old cars have ended up!