Reverse Backup Sensors are a must have for safety and piece of mind. Have you ever had an accident while backing up? Ever injured someone, or come way close to a child while backing up? Reverse Backing Systems backup sensors are the answer to your problem. Using ultrasonic waves, the sensors (whether mounted in the bumper or license plate frame) detect objects as far as 6 feet behind you and transmit a signal to either the LCD screen or speaker depending on the kit that is chosen. Make your daily drive a little easier with Reverse Backup Sensors from Reverse Backing Systems!