Complete kit includes 2 rear sensors and control module with piezo speaker Utilizes Ultrasonic technology to help detect what you can't see Automatically scans behind your vehicle to detect objects in your path as soon as reverse gear is engaged Sounds audible alert when you vehicle comes within 6 feet of an object or person Progressive alert tone increases in frequency as you get closer Designed to work in all weather conditions Sensors can be painted Available in Black(ASRSB), White(ASRSW), Silver(ASRSS) Additional sensors and optional LED display available Model: ASRSB