The Rostra 250-1903-BZP is a revolutionary parking assist system developed by Rostra Precision Controls designed to give every driver peace-of-mind while parking their vehicle in cramped quarters with a universal solution to color-matched sensors. The BackZone Plus audibly alerts drivers to the potential dangers of nearby obstacles through the use of an included buzzer built into a digital display that can be mounted on your sun visor or dashboard. When the vehicle is put into reverse, the system will sound a "beep" alerting the driver it has been activated. The system will further alert the driver to the presence of obstacles within each of it's detection zones. From a pulsing beep to a steady tone, the BackZone Plus system works to keep drivers aware of their surroundings. The system goes silent again only when an obstacle is no longer in range of contacting the vehicle. Included in every BackZone Plus automotive ultrasonic parking assist system, you will find four bumper-mountable ultrasonic sensors with additional bezels added to accommodate angled and steel bumpers. These sensors provide information to the main control module via the vehicle-length wiring harness, also included. As well, each BackZone Plus kit also includes a way of alerting drivers to objects nearby visually and audibly with the color digital distance display with it's built-in buzzer and distance from an object displayed in inches.