4K Superior Definition- 8 million pixels, 128° diagonal field of view. Smart AI Human Vehicle Detection-reduce false alarms and save storage space. Capture and Record Audio- Cameras capture sound and NVR record it. Output audio to a HD TV or mobile APP. IP66 Durable Housing- Metal housing, indoors or outdoors, fully weatherproof. Hidden Infrared Lights- enable relatively hidden infrared lights automatically at night, IR night vision up to 100ft.