The NuPhy Air75 HE has excellent build quality. While its top case is aluminium, the bottom chassis is plastic, so you can slightly flex the deck if you press hard enough. Despite that, the overall construction feels very sturdy with a tight fit and finish.

Both the stabilizers and switches come pre-lubricated from the factory. The stabilizers operate smoothly without noticeable rattle, and the switches feel very stable in their housing with minimal wobble.

Most of the keycaps are made of doubleshot PBT with a pleasant, slightly textured finish, but the keyboard also comes with nine transparent polycarbonate keycaps pre-installed. These let the backlighting shine through, but they feel a bit cheaper and slightly slippery. If you prefer, the box includes PBT replacements for all nine.

Layers of dampening material inside the case help round out the sound profile and slightly soften the typing feel. Small silicone dampeners under the spacebar also reduce the hollow sound and feel that some other keyboards suffer from.

On the underside, rounded rubber strips keep the keyboard firmly in place while typing, and rubber-capped flip-out feet provide two additional incline options with good stability.