Necessary if you have front and back plates. Less than $7.50 each! OUR EASY TO INSTALL LICENSE PLATE COVERS BLOCK YOUR NUMBER FROM BEING READ BY RED LIGHT, TOLL AND PHOTO RADAR SPEED CAMERAS. They fit on U.S. and Canadian plates, 12 inches by 6 inches, international covers will be available soon. Your license plate remains readable from vehicles directly behind you but unreadable from cameras located at an angle to your car as seen in our photo. This makes them discreet and virtually undetectable.