WD Red 2TB 3.5" SATA NAS Hard Drive 5400RPM 64MB WD20EFRX-68EUZN0
This unit has been fully tested and verified working, with zero bad allocated sectors and fewer than 50,000 power-on hours. SATA vs SAS: This is a SATA hard drive. This applies to both 2.5" and 3.5" drives.