Car Parking Aist System DC 12V Vehicle Reverse Backup Radar with LED Distance Display Sound Warning 4 Parking Sensors for Car Features: 4 sensor system, double CPU and advanced chipset for enhanced coverage and detection (0.25-2m). With digital colored LED display (number & light). Help to prevent dangerous and costly collisions. Help to provide increased safety for paengers, pedestrians and family members who happen to be around the moving vehicle. Detect small children and low walls as well. The display can show the position and distance of different obstacles Anti-freeze and rain proof. The closer the obstacle is, the faster the alarm sound, just like a human heart beating. Easy to install.Sensor's Diameter: 22 mm Specification: Rate voltage: 12V DC Rate operating range: 10.5V - 16V DC Rate current: 100mA - 300mA Detecting distance: 0.25 - 2m Ultrasonic frequency: 40KHz Control moudle working temperature: -30 - 80 celcius degree Main control box size: 90* 61 * 22mm sound: bibibi Package including: 1 * Main Control Box 1 * LED display (switch key with sound) 4 * Parking Sensors with 2.5m Line 1 * Hole Saw 1 * Power Cable 2 * Double Side Sticker 1* User manual