be quiet! Dark Base 900 PRO review - Product Showcase

 
A lovely big motherboard cutout so you can easily install a new cooler. Bear in mind that the tray can be reversed inside the chassis if you'd like to do so. Below that gap we see a PCB with lots of connectors.

The PCB is in fact a fan HUB for the three included fans. The PRO models get an extra four connectors free to use. The left side fans are PWM based, the extra four not so much, however can be RPM regulated by a fan controller located at the front side just behind the door panel. Also, if you purchased the PRO model chassis you can connect two extra LED strips (RGB) here as well. You power this unit with a SATA power connector. BTW next to the fan controller in the front there is a button, this can be used to select any out of the 5 preset colors for the LED RGB lighting. 

Included in the carton box is a manual, some tie-wraps / Velcro and a tool box containing a wide variety of assorted screws and the rubber strips / pads for HDD mounting. The two metal brackets are handy, the right one can be used to mount a water pump or reservoir. The mount to the left can be used to mount a third fan on the front side of the chassis. The PRO models get two LED strips (RGB) that can be regulated. These are glued to a stiff adhesive and have sticky tape applied so you can mount them easily to your preferred position. Each LED strip has a cable that you will need to lead towards the FAN / LED hub located on the backside of the motherboard tray, I'll show you that in another photo though.

Here is a side angled view of the inside of the chassis. There is a decent amount of space to work with inside the chassis mainly due to the large dimensions. Nice to see are the properly rubberized grommet holes, the good stuff that stays in place if you lead a wire / cable through it.
  

A rather simple design, but simple always works. Effective. The inside of the case is finished entirely in black including all wiring, and that complements most component choices quite well.
 

 
So I've mentioned the fan and LED controller a couple of times now, open the front door, and just above the optical units you can see a slider and a button. The slider (left to right) is used to in/decrease and regulate the fan RPM, the right side button switches primary RGB colors to the LED arrays (or turns them off).
  

 
If we move downwards a bit more we can see a removable dust filter that can be easily ejected. The two 140mm / 1000 RPM Silent Wings 3 fans now become visible and accessible.