Germany-based Be Quiet! made a strong impression with the Silent Base 800 in late 2014, delivering on all fronts including top-notch thermals, easy installation, an excellent build quality and plenty of features. Most impressive of all, that was their first desktop PC case ever developed.

Now approaching two years since we tested Be Quiet's initial creation, the company is taking things to the next level. In its most basic form, the new Dark Base 900 is a large well-made enclosure that makes good use of varying materials such as steel, aluminum and glass.

At its core, however, we've come to appreciate it as an engineering masterpiece that is without a doubt one of the most flexible and customizable computer cases on the market today. Almost every aspect of the case can be customized and changed in some way. Out of the box it appears similar to any other high-end full-tower case, but break it down and you'll quickly realize this is a different animal you have in your hands.

If you dismantle the Dark Base 900, which is much easier than it sounds, it can be reconstructed to look completely different to how it arrived. Like the recently reviewed Corsair Carbide 600C, the Dark Base 900 can become an inverted ATX case. By inverted we mean exactly that, the design turns the ATX form factor on its head flipping the motherboard upside down and therefore the case opens to the right rather than the left.

This has unique benefits which, depending on your preference, can be very useful. There are a number of other tricks that the Dark Base 900 is capable of thanks to its modular design, which we will get to shortly. Other key features include a beautiful tempered glass window for the 'Pro' model, high-end cooling configuration out of the box, support for a wide range of hardware, not to mention a premium fan controller and sound insulation.

Tour Around the Dark Base Pro 900

Like all Be Quiet! cases released to date, the Dark Base Pro 900 has a subtle, elegant design. After little more than a quick glance I knew this thing was going to be in hot contention for the best looking case of 2016.

The Dark Base Pro 900 is a predominantly black case that comes with either orange or silver highlights, but can also be purchased in all black as well, which I have to say looks very ominous. For review we have the orange version which we like to think of as the "official" model given the company's theme.

Anyway, it weighs a rather hefty 14.39kg empty, though a good bit of that is down to the massive glass side panel which we will look at shortly. The case is rather large as well of course, measuring 577mm deep, 243mm wide and 585mm tall.

The front is dominated by a single large panel split into two parts. To open it you simply press on the door and it pops out. Then to close it you simply push it closed and press it once, locking it into place.

Before we check behind the door let's take a quick look at what sits directly above. Here we find a sleek I/O panel featuring a pair of USB 3.0 ports, two USB 2.0 ports, HD audio jacks, activity lights and a nice big power button which also features active lighting.

A pair of embedded magnets hold the door closed, though they aren't super strong so the door opens with ease – easily enough that we'd tape it shut when working with the case. The door is lined with a noise absorbing foam and it's reasonably heavy thanks to a solid design and steel hinges.

Behind the door are two 5.25" external drive bays along with the fan speed controller which features a slider rather than a dial. The controller also integrates an LED switch for enabling or disabling the LED light strips that are supplied with the case.

Below the external drive bays we find a removable dust filter which clips out quickly and easily. Naturally this filters the air being sucked in by the front in-take fans so easy access is essential as it will require regular maintenance.

As mentioned, the Dark Base Pro 900 has a nice glass panel, but before we talk about that let's check out the opposite side as it's also quite interesting – I say opposite panel rather than right panel as it might be installed on the left side depending on the configuration.

The steel panel has been lined with more noise absorbing foam except a cutout towards the middle. This is part of the 2-in-1 side panel cover which can be used to install an additional two cooling fans. The panel has been recessed in a way that it still allows airflow even when installed, additionally though it can be removed for maximum airflow. It's important to note that fans can only be installed here if this door isn't placed behind the motherboard tray.

The tempered glass side panel is only featured on the 'Pro' model and covers the full height and width of the panel to show off the entire internal workings of the case. The glass measures 4mm thick, has a cool brownish tint and is secured in place via four thumbscrews, though it's decoupled from the chassis by rubber seals.

The top panel also looks pretty bland, but again there's a bit going on here. Just behind the I/O panel we looked at a moment ago there was a strange rectangular design element. However, this isn't there for aesthetic purposes, rather it's a Qi charger providing wireless charging for supporting devices such as smartphones for example. This cable free charger is a premium addition to the Dark Base Pro 900.

Further towards the back of the top panel we find some interesting cut outs, presumably for airflow. Indeed, they are! In fact, Be Quiet! tell us these are part of the "full circuit airflow system". They say the case utilizes an intelligent full-circuit airflow system with noise-dampened vents all around the case. These vents are L-shaped to avoid the air moving in a straight line, apparently broken is quieter, who knew.

Around back, the design is about as unusual as computer cases tend to get. The power supply appears as though it's mounted in the bottom of the case as suggested by the 3-pin plug and switch, both of which are normally found on the power supply itself. Along with sitting in the bottom of the case, the PSU is offset so it's inside the case, which is unusual to say the least and has been done so to accommodate the modular design.

Above the power supply area there are eight expansion slots, followed by the motherboard I/O slot and adjacent to that is a 140mm exhaust fan.

Underneath the Dark Base Pro 900 there is no ventilation at all, just a solid base and four custom feet with soft rubber pads that raise the case 25mm from the ground.