The reversing radar is designed based on the principle that bats fly at high speed in the night without colliding with any obstacles. The probe is mounted on the rear bumper. According to different prices and brands, the probes are divided into two, three, four, six and eight, respectively. The probe radiates at a 45-degree angle and searches for the target up and down. Its biggest advantage is that it can explore obstacles that are lower than the bumper and the driver is difficult to see from the rear window, and alarm, such as flower beds, children playing in the back of the car.