Amazon.com: Western Digital 4TB WD Blue PC Internal Hard Drive HDD - 5400 RPM, SATA 6 Gb/s, 256 MB Cache, 3.5,Western Digital WD BLUE 4TB 3.5 Inch (WD40EZAZ) Hard Drive HDD SATA - Tested,Western Digital Blue WD40EZRZ 4TB 3.5,WD Blue 4TB PC Hard Drive - 5400 RPM Class, SATA 6 Gb/s, 64 MB Cache, 3.5in - WD40EZRZ (Renewed)