New 4 Channel Embedded Linux US411ZS D1 H.264 Network DVR With 500GB Hard Drive, Real time True Triplex with built web server for remote viewing and operation, backup and operation 4CH DVR 480FPS SATA ready 4 Channels DVR Real time Triplex H.264 with 500GB SATA Hard drive installed H.264 DVR Technology, watch, plays back, record and login remotely all at the same time. With H.264 web server for Clear and smooth play back Compression format providing crystal clear images with real time performance Multiplex, Long-Recording Hours, SATA Hard drive ready no format or software need it plugs and play Allows live display, record, playback, backup and network operation at the same time.