Docooler&reg; Rainbow LED Display 4 Parking Radar Sensors Car Reverse Backup Radar Rearview Mirror Car parking system as well as rearview mirror. Can directly replace your original rearview mirror. 4 sensor system, double CPU and advanced chipset for enhanced coverage and detection (0-2.5m). With digital colored LED display: obstacle distance (meter) & multi-color light & word (STOP). With sound alert when the 4 sensors detect dangers: the closer the obstacles, the louder and faster the sound alert.