TKOOFN Highly Sensitive Buzzer Safety Alert Car Reverse Back Up Radar System with 4 Ultrasonic Parking Sensors & LED Display for Universal Auto Vehicle, Black Please do not touch or press the center of sensor, that would damage the sensitivity and cause disfunction Anti-freeze and rain proof Detect small children and low walls as well 4-sensor system, double CPU and advanced chip set to enhanced coverage and detection Help to provide increased safety for passengers, pedestrians and family members who happen to be around the moving vehicle