Once you look down in there you'll spot the innovatively placed drive cages and also a PCB. The PCB is simply used for the USB ports and guiding other IO. All USB connectors can be connected to the motherboards directly with their proprietary connectors by the way.
I'm adding some more exposure to the photo above to show you the innards a little better. The picture shows the drive bays from the left to right side of the case showing a 3.5 and 5.25" drive bay. The second 3.5" HDD rack is located under the 5.25" rack. It's also possible to mount two 2.5" drives on the outside of each of the 3.5" bays.
Important to note is that the interior of the case as well is made out of lightweight Aluminum, including the drive bays. All the bays are held in place by two guiding location pins and a screw to secure the unit. Though at first it looks a little daunting, they are relatively easy to remove and fit.
Here we removed the three cages. Once you get the hang of it and understand how they've been positioned inside. Quite clever really and also very sturdy seated.
XigmaTek GIGAS review SSF / MicroATX cases are typically smaller than typical ATX towers. This means that although the same standard hardware is supported, it is supported in lower quantities. Typically these boxes are used as a suitable HTPC home (home-theater personal computer), but with the looks the GIGAS offers, it would make a great gaming system as well as even lengthy graphics cards, ( up-to 320mm (12.5 inches) can be installed.