OWC Thunderbay can use Hard Drives or SSDs and Handy for Swapping Drives of all Types
The OWC Thunderbay can take full size hard drives, but it can accept take SSDs using the Newer Technology AdaptaDrive bracket bolted into a Thunderbay drive carrier. The carrier can then be inserted into any of the four Thunderbay bays.
This was really handy for some recent testing; I really like having a spare Thunderbay into which I can insert backup drives, SSDs for testing, etc. With a few extra drive carriers, the unit is really versatile, and the single power and Thunderbolt data cable is a dream compared to aging eSATA and miniSAS gear.