WD Network hard drives are designed and tested to meet the unique requirements of NAS systems with up to 5 bays. They are engineered to run cool and quiet while offering optimum compatibility for demanding 24x7 environments. These reliable drives are backed by an industry-leading 3-year limited warranty. 1TB Network NAS HDD, SATA 6 Gb/s, 5400 RPM, 64 MB Cache.