A 4-channel NVR (Network Video Recorder) is a compact surveillance system that supports recording and managing video from up to four IP cameras. It provides high-definition video storage, remote access via mobile apps or web browsers, and features like motion detection, playback, and data backup. Many models offer PoE (Power over Ethernet) for simplified installation and reliable connectivity. A 4-channel NVR is best suited for small-scale security setups such as homes, offices, and retail shops, offering an affordable and efficient monitoring solution.