ANNKE 4K 16 Channel PoE NVR with 2TB Hard Drive, Ultra HD Home Security Network Video Recorder Supports 4K/8MP/5MP/6MP/4MP ANNKE PoE IP Cameras, 24/7 Surveillance Recording

Product description PoE NVR Video Recorder Ultra-Convenient PoE Setup Works With/Without Internet Only one PoE cable is required for power and data transmission, enabling the simple DIY installation.

Setup your own security system is that easy! When the HDD becomes full, it'll automatically overwrite the oldest data with new ones.

So you just need to save vital footage before overwriting.