When reversing the car, packing sensor detect the obstacles behind the car automatically. Detecting range: 0.35m-2.5m after the car. Sound warning range: 0.0m-1.5m. Three segment real person voice: safe, be care for and stop Digital showing the distance between the obstacle and the car and the surveying precision can be 1cm. Showing front, back, left and right direction of obstacle with four different color. Two to eight sensors are optional. Power voltage:10V-15V (24V) Power consumption:<3W Warning volume>80db Working temperature: -40-80°C