The complete name of this product is MB559US-1S, and it houses a single 3.5" hard drive. Please pay attention to the interface, as the IcyDock enclosure only supports Serial ATA hard drives - the UltraATA interface is not supported.
The vendor provides an eSATA bracket (so you can convert an internal SATA port for external use with eSATA cabling), eSATA cables and a USB cable. The USB connection should only be used as fallback or for occasional use, as Serial ATA is far superior (see the benchmark section for our test results). Any modern 3.5" hard drive delivers higher data transfer rates compared to those offered by USB 2.0 by a factor of two.
The Icy Dock is very handy if you want to connect and remove it to and from different computers. Both eSATA and USB 2.0 are hot-plug capable, so you can plug the IcyDock in and use it without mounting it. However, you cannot use both interfaces at the same time - which would have been great to connect the drive to two computers at once.
We like that there is no speed difference for the Barracuda 7200.9 drive whether it is installed in the test system or runs as the IcyDock drive, which makes it possible to even use IcyDock for your system hard drive. The removable frame makes the solution suitable for entry-level backup: Purchase several drive frames and you may swap hard drives to do your backups on different days of the week.