Western DigitalWD Purple 8TB Surveillance 3.5" Internal Hard Drive - AllFrame AI - 360TB/yr, 256MB Cache 7200 RPM Class

WD Purple 8TB Surveillance 3.5" Internal Hard Drive - AllFrame AI - 360TB/yr, 256MB Cache 7200 RPM Class

WD Purple 4TB Surveillance 3.5" Internal Hard Drive, AllFrame Technology, 180BT/yr, 256MB Cache, 3 Year Warranty

Western Digital Purple 4TB Surveillance 3.5 Inch SATA 6 Gb/s Hard Disk Drive with Allframe 4K Technology - 180TB/yr, 64MB Cache, 5400rpm - WD40PURZ