CAHDD3001T01 Hard Drive Array is perhaps the easiest and most cost-effective way to consolidate the storage of any two hard drives (included). 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 new volume will be read as one drive with combined capacity when set to Spanning (BIG). And the BIG/JBOD settings are easy to change as well just use the switch on the back of the dock. Your extra hard drives can finally be put to good use with this versatile dock. And with no clumsy cover to unscrew or disassemble, your hot-swappable drives are always accessible and well-ventilated, without a noisy fan. With the USB 2.0 interface and stable, compact base, the "Cavalry Dock" is perfect for your home or office desktop computer.