That is a mechanical keyboard I have built myself.
“A mechanical keyboard is a keyboard built with high quality, typically spring activated, key switches. These key switches vary based on the keyboard’s application or user preference.”
If you wonder why I did that : Highest quality Make the design you always dreamed of. (frame & keys) Adapt the key pressure for your fingers. (put link) e.g. : The strongest keys pressure are ENTER, ESCAPE & SPACE key. The main keys need a normal pressure, and the bottom ones are the softest one because used by my little finger & thumb. I type 2-3times faster with it. You especially feel it when you type the super long password of your password vault. Flash your own customized firmware and define EVERY SINGLE key. So you can make any shortcut (directly on hardware implementation). It is more sustainable. You can upgrade it & fix it. I’m not planning to buy any new keyboard.
Ok, you have to know that it is still difficult to make it yourself, it needs a lot of time, soldering skills, and ~200€. You deserved some extra pictures, here you go :