Aunoc Mini LED Display 4 Sensors Kit Dual CPU Car/Truck/Vehicle Reversing Parking Sensor/Backup Sensor/Reversing Sensors System Radar Buzzer System,Periodic Buzzer Alarm, LED Rader,Three Stage Bi-Bi Sound Alarm System - Black Color 4 sensor system, double CPU and advanced chipset for enhanced coverage and detection Digital LED display, show the distance and the direction between your car and the back obstruction With Bi.Bi.Bi alarm, the closer, the more rapid alarm Help to prevent dangerous and costly collisions, enhance the safety features with simple installation Help to provide increased safety for passengers, pedestrians and family members who happen to be around the moving vehicle