Defender SENTINEL4 Web Ready 16 Channel DVR Security System Digital Video Recorder with 16 Indoor/Outdoor Hi-Res Night Vision Surveillance Cameras 320GB Removable HDD - Store up to 750 days of footage on this removable, lockable hard drive (DVR must be turned OFF to remove HDD). CF Card Backup - Transfer video footage to a Compact Flash card for archiving or offsite viewing not included. Motion Activated Recording - Set the DVR to record only when motion is detected and alert you with an audible beep. 16 Hi-Res Indoor/Outdoor CCD Cameras - Clear, crisp and consistent picture at 420 TV lines of resolution. Internet Accessible (Supports DDNS) - View live or recorded footage from any computer with Internet Explorer