This is a case for the custom "Antares" keyboard. It is one of the - if not THE - smallest usable mechanical keyboards that's available at the moment. Here's a full part list for the board:
30x Mechanical Mx switches
30x Diodes
Wire
Pro-Micro/ Teensy Microcontroller
Micro-usb Cable
Silicone feet (10mm)
Keycaps
Here's a build-log on how to build and assemble the board.
Designer: Zorberema