It's a hotswap, gasket mount board with RGB lights, and both wired and wireless modes.
From the Melgeek product page:
Get the best keyboard customization experience. The main concept of Pixel is to have a beautiful and fun keyboard with endless customization possibilities.
The key characteristics of this keyboard model is that both the two-part keycaps and the relatively spacious surface area of the case, and the bottom as well, are LEGO compatible.
According to the manufacturer, the main advantage of the Pixel keyboard is that "you can create any pattern and three-dimensional shape through the bumps around of the keyboard".
Pixel keyboard keycap structure
That means, while the Pixel keyboard is available in three colors, you can customize your board using any LEGO bricks and compatible building blocks.
I tested KBDcraft's brilliant Israfel, a 50% unibody split with an adjustable angle, made of LEGO. It's impressive and offers a huge bang for your buck. Flock to the store, folks!