Cavalry CAHDD Series USB Dual-Bay Dock 4 TB (2x2TB 3.5-Inch SATA Hard Drives) CAHDD3004T02 Two-bay dock for easy consolidation of storage Two (2) 2TB 16MB 7200 RPM SATA II drives Hot-swappable bays with open design for access and ventilation Supports JBOD and BIG (Spanning) configurations Transfer rate of 480Mbps (USB 2.0)