Summary: I made the folowing review about the single unit and it is a good one to have also, but now I want to leave this review (copy of my first one earlier) for others to see who bought the dual one. This device is a simple way to insert a 2.5" drive into an existing computer to be able to look at the drive contents or test it as the case may be. It is also a good way to copy off the contents of the drive which you wish to keep if you are going to be selling the drive.
Pros: this little item is a fantastic idea except for no cooling fans but you should use caution and make or design somehow yourself how to put a cooling fan in there and you should always be careful plugging in your cables.
Summary: As laptop drives have become more powerful they've become viable alternatives to desktop drives. The Vantec bay is plastic but can pass for metal from a little ways away. The trays need no tools, being removed by squeezing the front clips, and have pins inside to mount the drive--just pull it a little and out comes the drive. You need two SATA ports and power connectors, and it's NOT hot swap. You need to power your computer down before removing the trays.
Pros: Holds 2 2.5" drives at once which makes it very easy to copy between two drives without having to open your case . Swapping out hdds in this thing is a breeze just pull the tray out swap drives and it slides right in. comes with very useful molex power connectors to sata connectors.
Cons: This Drive bay sometimes makes the drives really hot especially if you are using them a lot. Also like the other people have said the HDD lights on this thing are blinding at the right angle. The sata plug-ins in the back are kinda flimsy but have not had them fall out yet.