The professional car parking sensor consists of ultrasonic sensors， digital control box， and LED display.This system detects the distance between the car and back obstruction with ultrasonic sensors installed at the rear bumper of car. Features:LED digital display with BiBi sound reminder.4 sensor system， double CPU and advanced chipset to enhanced coverage and detection.Be beneficial to prevent dangerous and costly collisions.Help to provide increased safety for passengers， pedestrians and family members who happen to be around the moving vehicle.Detect small children and low walls as well.Anti-freeze and rain proof.Easy installation and operation.With a drill head， convenient to drill hole.Specifications:Sensor color: BlueRate voltage: DC12VOperation voltage range: 9-16VRate current: 20mA-200mADetecting distance: 0-2.5mUltrasonic frequency: 40KHzControl moudle working temperature: -30 - +70 celcius degreeDisplay working temperature: -20 - +60 celcius degreeSensor size(H * D): 1.9 * 2.5cm / 0.75 * 0.98inLED display size: 9.9 * 2 * 2.6cm / 3.9 * 0.79 * 1.02inMain control box size: 10.5 * 6 * 2.3cm / 4.13 * 2.36 * 0.91inDisplay weight: 89g / 3.15ozMain control box weight: 63g / 2.22ozItem weight: 355g / 12.52ozPackage includes: K369BL1 * Main Control Box1 * LCD Display Indicator4 * Sensors with 2M Line1 * Hole Saw1 * Power Cable2 * Double Side Sticker1 * User Manual