Specifications: 1.Measuring the distance by radar 2.Alarm by three step Bi-Bi sound 3. 4 rear sensors are available 4.Full-weather design, un-affected by wind, ice, snow & rain 5.All kinds of sensor colors and styles are available 6.High quality and easy to install Technical Parameters: 1.Rated Voltage: 12V DC 2.Operating Range: 10.5V to 16V DC 3.Rated Current: 50mA to 180mA 4.Detecting Distance: 0.3 to 2.0m 5.Ultrasonic Frequency: 40KHz 6.Display Working Temperature: -30 to +70 Centigrade