Western Digital WD40EFRX Red 4TB 3.5" 5900RPM Internal Hard Drive. The WD Red 4TB Hard Drive is optimized for NAS systems and built to withstand the rigors of 24/7 operation. If you need 4TB of network accessible space, this NAS-ready continuous operation hard drive offers high capacity and unmatched reliability. Back up your files and access them from anywhere in your home or office quickly and efficiently when you use a NAS enclosure with this NAS-ready 4TB hard drive. The WD Red 4tb hard drive is a great drive for NAS and long-running drives. 4TB SATA 6Gbs 64MB Red Drive. SINGLE BULK PACK WD Red is designed specifically for NAS systems that have 1 to 5 drive bays in both 3.5-inch and 2.5-inch form factors. The drives are designed and extensively tested for compatibility in the unique 24x7 operating environment and demanding system requirements of home and small office NAS.
The WD40EFRX hard drive from Western Digital features 4TB of storage size in a 3.5" form factor. This drive connects to your system via the SATA 6 Gb/s interface so make sure you have an available port on your compatible motherboard. Advanced features of this HDD include a 64MB cache/buffer and 5400 rotational spin rate.