Features: 1.Based on the reflection principle of electromagnetic wave 2.Detect and indicate the distance of obstacles behind cars 3.Detection in all directions without dead angle 4.During approaching to an obstacle,the electronic unit activates the acoustic signal with beeping 5.Easy installation,totally built-in mounting .The sensor antenna is installed inside the bumper,no need for drill on the bumper. Specifications: 1.Working voltage:DC12V+/-2V 2.Currecy consumption:< 50mA 3.Working temperature:-20°C ~ +70°C 4.Detection range :Approximately in 0.7m 5.A continuous sound of "BEEP" approximately between 0-0.3m 6.A short interval sound of "BEEP" approximately between 0.3-0.5m 7.A long interval sound of "BEEP" approximately between 0.5-0.7m Components included: 1.Electronic box 2.Antenna sensor 3.Buzzer or display 4. LED display