Audiovox ACAB104 4 Sensor Back-Up Obstical Sensing System (Black) Automatically Scans Behind Vehicle To Detect Objects In Vehicle'S Path As Soon As Reverse Gear Is Engages Utilizes Ultrasonic Technology To Help Detect Less Visible Objects 4 Reversing Sensors Detection Range: 1 Ft7 Ft 19.5-Ft Sensor Wire Length