Features: 4 sensor system, double CPU and advanced chipset for enhanced coverage and detection (0-2.5m). High sensitivity. With sound alert when the 4 cameras detect dangers. The closer the obstacles, the louder and faster the sound alert. Help 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 to install. A saw drill head included.