A Closer Look - Inside
Simply remove the four screws holding the side panel in place to gain access to the interior of the chassis. Once taken off, you can clearly see the cage with the two hard drive bays on the bottom. The cage is right next to the air vent of the side panel, so the drives and anything behind it get as much fresh air as possible. You may take this cage out by removing four more screws. Once this is done, there is nothing but the bare case left to work with.
Taking a quick look at the rear from the inside, it becomes apparent that Cooltek has really gone for the bare minimum in terms of motherboard spacing as there is very little space to work with below the expansion slots. There is a small square cutout below the fan grill. It appears to be for a small switch of some sort; maybe one to adjust the fan speed. Cooltek may offer something along those lines as an accessory, but your guess is as good as mine as such extras have not been included. Above that are the two additional spots for 80 mm fans, bringing the total up to three. Just like with the smaller Coolcubes, no cooling fans have been included.
You can install a single hard drive of 3.5" or 2.5" to the floor of the chassis. Cooltek ships the chassis with four rubber rings that may be used as a protective measure against vibrations.
Two black PCBs are screwed to the interior side of the front. One holds the power button and LEDs, while the other is used to implement the I/O on the side of the chassis. Both come with black cabling and traditional connectivity. A nice touch would have been the inclusion of a USB 3.0 to 2.0 adapter of some sort, as users with older boards cannot use the modern USB connectors.