Cooler Master MasterBox NR400

The Cooler Master MasterBox NR400 is designed for mATX (micro-ATX) motherboards, not full ATX boards, as part of its compact micro-tower form factor. This makes it suitable for smaller builds where space is a priority. Users who need full ATX support should look at Cooler Master's larger mid-tower offerings in the MasterBox or MasterCase lineups.

The MasterBox NR400 can accommodate graphics cards up to approximately 361mm in length, depending on drive configuration. This allows it to fit many modern mid-range and even some higher-end GPUs despite its compact size. Users should verify clearance if they have front-mounted storage drives that could reduce available space.

Yes, the MasterBox NR400 features a tempered glass side panel that showcases internal components and RGB lighting. This version is aimed at builders who want to display their setup. Cooler Master also offers variants of the NR400 with solid steel panels for users who prefer a more utilitarian look.

The MasterBox NR400 is a compact mATX case, so CPU cooler clearance is limited compared to full-size towers, typically accommodating coolers in the range of standard tower air coolers rather than very large models. Users planning to use a tall air cooler like a Noctua NH-D15 should verify exact clearance specifications before purchasing. The case is generally better suited for stock coolers or compact aftermarket options.