WD Red 3.5" NAS Hard Drive WD120EFAX - Hard Drive 12TB - SATA 6 Gb/s. 3.5-inch form factor. Interface Rate 196 MB/s. 5400 RPM class. 180 Workload Rate. 256 Cache. Small and home office NAS system in a 24x7 enviroment. 3 Year limited warranty. SINGLE PACK