Numeric display of distance from obstacle. Auto power when reverse gear is engaged. More features, small volume & lightweight. Can simultaneously observe the three sets of data stream. 4 sensor system, double cpu and advanced chipset for enhanced coverage and detection. Multistage LED display. Water resistant silicon sensor. Anti-freeze and rain proof. Easy to install. With digital colored led display (number & light). 5. Bi bi bi alarm prompts step by step, 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.