WD Red 750GB NAS Hard Drive - 5400 RPM Class, SATA 6 Gb/s, 16 MB Cache, 2.5" - WD7500BFCX Optimal compatibility for NAS systems Tested for 24x7 reliability Specifically designed for use in NAS systems with up to 8 bays 3-year manufacturer's limited warranty Designed for the unique system requirements of NAS environments