Reversing Parking Sensors 4 Sensor Kit Four detectors(color selectable)Five different frequencies of alarm sound according to distance With this Parking Sensor system installed, drivers can lower the risk of accident. This affordable parking sensor enhances the proce of parallel and backup parking designed for your concerns about safety and for vehicles that have poor rear visibility. The system will work automatically to detect the obstacles at the rear of your car at any time. All parts are designed with profeional grade quality. Specifications: Operating voltage: DC 12V Operating current: 200mA 50mA Alarming type: Buzzer/LED Operating Temperature: -20c ~ +70c Detective range: 0.3m ~ 2m Alarm Voice: >70dB Detective angle: H:80 V: 70 Diameter of sensor: 25mm Cable of sensor: 2.5m Cable of monitor: 4m The alarm sound would become more rapid when the distance gets shorter and shorter, alarm mode and danger mode. How does it work?The system is automatically activated when you engage reverse gear. Small sensors are receed to the rear of the vehicle, they send and receive ultrasonic radio waves, which bounce off obstacles and alert you to their presence. The internal buzzer that gradually increases in frequency as you approach the object. How to install? There is"UP"on the detector, please keep the arrow upwards when install it; It will be the best to install detectors of a height about50-60cmfrom the ground; Connect red and black cable seperately to the positive/ negtive pole of the reversing lamp. Packing list: