The be quiet! Dark Base 900 Full-Tower is an exceptionally versatile and quiet case that combines modularity, compatibility and functionality in one. Apart from the extensive array of configurations possible, the case also offers three pre-installed be quiet! SilentWings 3 PWM fans and provides the potential for superb air- and water cooling. The distinguishing characteristic of this case could be said to be the way it intelligently combines high-end materials with useful everyday functions, making the Dark Base 900 the perfect housing for a high-end gaming system, overclocked of course, or a watercooled system that operates in near silence.The be quiet! Dark Base 900 Full-Tower at a Glance:Modular interior thanks to versatile motherboard tray and HDD slotsIntelligent airflow & extensive air- or watercooling possibilitiesThree pre-installed be quiet! SilentWings 3 PWM fans2-in-1 side panel for silent operation or two additional 120 mm fansSpace for an E-ATX-, XL-ATX-, ATX-, Micro-ATX- or Mini-ITX motherboardPWM Hub & manual fan controlsI/O Panel with 2x USB 3.0, 2x USB 2.0 and HD AudioModular Interior with Multiple Options for UsersThe stylish Full-Tower supports motherboards from E-ATX, XL-ATX, ATX, Micro-ATX down to Mini-ITX, this is due to the fact that the motherboard tray is designed in a manner versatile enough to meet the precise requirements of the user. As a result, it is fully height adjustable and can be installed on the left side of the case (inverted) for a fresh new look or to change the case\'s airflow characteristics. Moreover, it can be completely removed in order to serve as a bench table. The ODD cage as well as the drive slots are similarly adjustable and customizable, the sum total of these design choices is a case whose interior allows users to have things set up in just the way they want. Apart from the modular configuration options that be quiet! offers, the Dark Base 900 also holds up to two 5,25\"-, seven 3,5\" and/or fifteen 2.5\" drives. The drives can be installed without the need for tools into individual slots, slots which enjoy the added benefit of silicon anti-vibration rails designed to minimize the transfer of vibrations to the cages. Furthermore, the slots can be removed on an individual basis to even enable users the option of increasing the space available to graphics cards or watercooling components. The added space this case offers comes in handy for a lot of high-end hardware, enabling graphics cards up to a length of 325 mm to be installed. Without HDD slots, this space increases to a full 470 mm. CPU coolers up to a maximum of 185 mm in height and PSUs from 150-184 mm long will fit in the Dark Base 900 with ease.Premium Design with Elegant AestheticsThe design of the be quiet! Dark Base 900 remains, as was the case in previous models, both elegant and stylish, making a great first impression. What is new, however, is the 2-in-1 side panel that offers an opening which can either be closed (for silent operation) or left open and kitted out with two further 120 mm fans. The closed front and the roof both offer attractive brushed aluminium. The side panels have black mesh strips around the edges to aid in providing optimal airflow. As was also the case with its predecessors, be quiet! opts against typical \"gaming\" aesthetics and instead focuses on providing a more elegant look.Smart Air Cooling or WatercoolingThree 140 mm SilentWings 3-PWM fans come pre-installed in the Dark Base 900, two in the front and one in the back. The fans operate at up to 1.000 RPM and, thanks to their low vibration motors and durable fluid-dynamic bearings, and their funnel-shaped air vents, operate exceptionally quietly. The airflow design of the Dark Base 900 Full-Tower also opts to use innovative noise dampening air vents around the case, these are also designed to optimize airflow. In order to maximize the case\'s ability to operate at low noise levels, the case is also fully insulated and even includes spacers on the motherboard tray, PSU tray and the drives. When it comes to air cooling, users have free rein. The roof alone can support up to four 140 mm fans, although 4x 120-, 1x 180- or 1x 200 mm could also be installed. The bottom of the case offers space for two 140 mm- or 120 mm fans. The front can, with the ODD cage removed, support a further 120- or 140- fan. Of course the aforementioned locations can also be used for mounting radiators in order to watercool your PC. The front offers space for a