Drobo 5Dt: 5-Drive Direct Attached Storage (DAS) Array with mSATA SSD acceleration - USB 3 and Thunderbolt 2 ports (Empty) DRDR5A21-T 2 x Thunderbolt 2 & 1 x USB 3.0 Holds up to 5 x 3.5-Inch SATA HDDs Includes mSATA SSD for performance increase of up to 3x Includes 3- year DroboCare On-line and Instant capacity expansion