This B&H Kit includes the Drobo Mini 4-bay Enclosure Kit and Four 1TB 2.5" Mobile Hard Drives. Combine these four 1TB hard drives with the hot swappable 4-bay enclosure to safely store up to 4TB of data. The Drobo Mini's BeyondRAID Technology features single or dual-drive redundancy for added protection of your data. When saving your data, you can utilize each drive's SATA 3Gbps interface and 7200RPM drive speed. For quickly transferring data to your computer, you can take advantage of the enclosure's Thunderbolt and USB 3.0 ports. Plus, you can daisy-chain up to six Thunderbolt devices and/or a non-Thunderbolt monitor at the end of the chain.