The Cavalry Dock is perhaps the easiest and most cost-effective way to consolidate the storage of any two hard drives. This two-bay, hot-swappable USB 2.0 dock is perfect for lumping together your odd-capacity drives into one Spanning device, just insert any two 2.5? or 3.5? SATA drives. Your PC will read the drives as one large drive with combined capacity of the two drives you installed. Once connect to you PC's USB port, with the flip of a switch, the Cavalry Dock will automatically copy the contents of one drive to another. Or you can have an external hard drive with an exact duplicate of the contents on a second drive. And the BIG/JBOD/RAID 1 settings are easy to change as well just use the switch on the back of the dock.