Seagate SkyHawk 4TB Surveillance Hard Drive - SATA 6Gb/s 64MB Cache 3.5-Inch Internal Drive (ST4000VX007)
Amazon.com: Seagate SkyHawk 8TB Surveillance Internal Hard Drive HDD – 3.5 Inch SATA 6Gb/s 256MB Cache for DVR NVR Security Camera System with Drive Health Management (ST8000VX0022) : Electronics
Amazon.com: Seagate SkyHawk 6TB Surveillance Internal Hard Drive HDD – 3.5 Inch SATA 6GB/s 256MB Cache for DVR NVR Security Camera System with Drive Health Management – Frustration Free Packaging (ST6000VX001) : Electronics