Security Labs SLD254 4-Channel DVR (Black) Dual Stream H.264 Codec Records Highest Quality To Hard Drive & Optimizes Internet Transmission Speed Simultaneously 500Gb Hard Drive Included, Expandable Up To 2Tb Email and Sms Text Messages Can Be Sent With Images When Activity Is Detected Monitor and Control Select Functions Via The Internet With A Pc Or Smartphone Selectable Grid Video Motion Detection Pinpoints Areas To Be Covered & Helps Eliminate False Alarms