A Closer Look - Outside

In terms of looks, the Masterbox NR400 for the most part doesn't dare go beyond what you would expect to see from a pretty generic chassis. The front is made out of metal mesh and framed with plastic. While we have the variant without an external drive bay, Cooler Master also offers the chassis with a 5.25" drive bay.


The front does not have a real design element with the exception of a subtle stripe down one side. As the NR400 is also aimed at system integrators, Cooler Master has chosen not to place their logo here. You may pull the panel off the chassis to reveal a single 120 mm intake fan with the ability to add two more such units. A radiator of up to 360 mm will also fit behind the fan, but you will have to sacrifice the 5.25" drive bay. If you would like to keep the drive bay, the NR400 still allows for a 280 mm rad in this area. Looking at the rear, everything is where you would expect it to be with the PSU bay on the bottom of the Masterbox.


One of the somewhat unique elements is the glass side panel that only covers about 80% of the case, while the rest is actually the frame itself. We have seen this from other brands as well, and it is an approach that works quite well. The other side panel is pretty classic and constructed out of metal.


The PSU bay in the rear comes with two sets of mounting holes and is otherwise pretty standard. Above that are the four expansion slots. As the screws holding the individual covers in place are outside of the case, Cooler Master has placed an extra cover you will need to remove during assembly here. In the very top is a 120 mm exhaust fan, bringing the total number of included cooling units to two, which is exactly what we would expect to see.


In the top, you may install a 240 or 280 mm radiator or respectively sized fans. In addition to this, Cooler Master includes a magnetic dust filter to cover this area up and protect the interior from dust. The I/O of the NR400 is actually quite basic. You will find two USB 3.0 ports, but only a single combo audio jack, which is quite the departure from the dual plugs we have seen for years.