American Dynamics ADD800LTPV050 LT SERIES 8 CHANNEL 500GB
Amazon.com: Western Digital WD AV-GP 500GB 32MB Cache SATA 3.0Gb/s 3.5inch (CCTV DVR, PC) Internal Hard Drive (Low power, Quiet) -w/1 Year Warranty : Electronics
Amazon.com: WL 500GB 16MB Cache 5400RPM SATA II (3.0Gb/s) 3.5" Internal Surveillance DVR Hard Drive - w/ 1 Year Warranty : Electronics
Amazon.com: MaxDigitalData 500GB 8MB Cache 5900PM SATA 6.0Gb/s 3.5" Internal Surveillance CCTV DVR Hard Drive (MD500GSA859DVR) - w/ 2 Year Warranty : Electronics