4TB Storage Capacity , 3.5" Form Factor , SATA III 6 Gb/s Interface , 256MB Cache , 5400 rpm , Up to 202 MB/s Sustained Transfer Rate , 1 Million Hours MTBF , 180TB Yearly Workload Rating , Air Sealed

6TB Storage Capacity , 3.5" Form Factor , SATA III 6 Gb/s Interface , 256MB Cache , 5400 rpm , Up to 202 MB/s Sustained Transfer Rate , 1 Million Hours MTBF , 180TB Yearly Workload Rating , Air Sealed

8TB Storage Capacity , 3.5" Form Factor , SATA III 6 Gb/s Interface , 256MB Cache , 5400 rpm , Up to 202 MB/s Sustained Transfer Rate , 1 Million Hours MTBF , 180TB Yearly Workload Rating , Air Sealed

12TB Storage Capacity , 3.5" Form Factor , SATA III 6 Gb/s Interface , 256MB Cache , 7200 rpm , Up to 240 MB/s Sustained Transfer Rate , 1 Million Hours MTBF , 180TB Yearly Workload Rating , Air Sealed

HDD WD 1TB NAS Red Plus SATA3(6Gb/s) 64MB 5400RPM 

HDD WD 2TB NAS Red Plus SATA3(6Gb/s) 128MB 5400 RPM 

HDD NAS PRO 12TB SATA3(6Gb/s) 7200RPM 256MB

HDD NAS PRO 2TB SATA3(6Gb/s) 7200RPM 64MB

HDD NAS PRO 4TB SATA3(6Gb/s) 7200RPM 256MB

HDD NAS PRO 6B SATA3(6Gb/s) 7200RPM 256MB

HDD NAS PRO 8B SATA3(6Gb/s) 7200RPM 256MB

HDD WD 6TB NAS Red Plus SATA3(6Gb/s) 128MB 5640RPM