Amazon.com: Western Digital WD40EFRX WD Red NAS Hard Drive - Hard drive - 4 TB - internal - 3.5 inch - SATA 6Gb/s - buffer: 64 MB - for WD My Cloud
Amazon.com: Western Digital WD40EFRX WD Red NAS Hard Drive - Hard drive - 4 TB - internal - 3.5 inch - SATA 6Gb/s - buffer: 64 MB - for WD My Cloud ,Amazon.com: Western Digital 4TB WD Red Plus NAS Internal Hard Drive HDD - 5400 RPM, SATA 6 Gb/s, CMR, 128 MB Cache, 3.5,Amazon.com: Western Digital 4TB WD Red Plus NAS Internal Hard Drive HDD - 5400 RPM, SATA 6 Gb/s, CMR, 64 MB Cache, 3.5