Will sell with 5 x 2TB Western Digital Enterprise Drives if you are looking for some serious storage (Price Neg).
Drives:
Accommodates from one to five 3.5″ SATA I / II / III hard drives of any manufacturer, capacity, spindle speed, and/or cache. No carriers or tools required.
Capacity:
Up to 20 TB capacity (4TB x 5 3.5″ Drives)
Single Disk Redundancy: 14.52 TB Storage/3.66TB Used for Protection/26.07 GB Overhead.
Dual Disk Redundancy: 10.89 TB Storage/7.29 TB Used for Protection/19.55 GB Overhead.
Connections:
USB 3.0 (USB 2.0 compatible) x 1, FireWire 800 (FireWire 400 compatible) x 2, and eSATA x 1
Compatibility:
Drobo connects to Mac and Windows systems and supports HFS+, NTFS, and FAT32 file system formats.