Inforad Manager uses GPS technology to warn you of speed cameras. It's completely road legal and easy to use simply place it on your dashboard and plug it in. GPS receivers such as Inforad use these satellite signals to define their position to within a few metres and to calculate the exact speed of your vehicle. Your Inforad knows where you are and your exact speed at all times through its radio connection to the GPS satellite network. Your Inforad calculates the distance to the next risk area. As you approach, the alert system issues a warning before you reach the exact location of the risk.