Amazon.com: White Label WL 4TB 7200RPM 64MB Cache SATA 6.0Gb/s (Enterprise Grade) 3.5" Hard Drive (for Server, RAID, NAS, DVR, Desktop PC) w/1 Year Warranty : Electronics
Seagate Enterprise Capacity HDD v5 ST4000NM0035 4TB 7200RPM 128MB Cache 512n SATA 6.0Gb/s 3.5" Internal Enterprise Hard Drive OEM - w/5 Year Warranty - Walmart.com
Amazon.com: Seagate BarraCuda Pro 4TB Internal Hard Drive Performance HDD – 3.5 Inch SATA 6 Gb/s 7200 RPM 128MB Cache for Computer Desktop PC, Data Recovery (ST4000DM006) : Electronics
SATA) Internal HD 3.5" 4TB 7200rpm 64MB HDD for PC, TP4000FYYZ | eBay
WESTERN DIGITAL 4TB 7200RPM 6GB/S 3.5" HARD DRIVE WD4004FZWX-00GBGB0 C1-1(15) | eBay
Seagate FireCuda 4TB 7200 RPM SATA III 6Gb/s 3.5" Internal CMR Hard Drive - Micro Center
HGST Ultrastar 4TB 7200RPM 64MB Cache SATA 6.0Gb/s 3.5inch Internal Desktop Hard Drive (for PC, Mac, NAS, RAID, Surveillance System) - 3 Year Warranty - Walmart.com