DS18 DS18 PRKB4 Car Reverse Backup Radar with 4 Parking Sensors with Buzzer - New High Performance Technology, Audible Warning Buzzer. Detachable Sensor with Waterproof Socket Connector. Input Signal Automatically Boots. Voltage: 12V DC Rate Current: 10mA ~ 150 mA. Detection Distance: 1 to 8 Feet for Rear. Ultrasonic Frequency: 40KHz Working Temperature: -30C ~ +80C