Amazon.com: Seagate Enterprise 4TB Internal Hard Drive HDD – 3.5 Inch SATA 6Gb/s 7200 RPM, 256MB Cache (ST4000NM004C) : Electronics
Purple HDD 1tb 2tb 3tb 4tb 6tb 8tb SATA 3.5' Hard Drive Disk for CCTV Camera Ahd DVR IP NVR Purple HDD - China Hard Drives for Camera and HDD for Security
WD BLACK Gaming 4TB Internal SATA Hard Drive for Desktops WD4005FZBX/WDBSLA0040HNC-NRSN - Best Buy
Seagate BarraCuda Mobile Hard Drive 4TB SATA 6Gb/s 128MB Cache 2.5-Inch 15mm (ST4000LM024) - Walmart.com
Seagate 4TB BarraCuda SATA 6Gb/s 256MB Cache 3.5-Inch Internal Hard Drive (ST4000DM004) Single Pack - Walmart.com
Synology 4TB HAT5300 SATA III 3.5" Internal Enterprise