StremDeck

That is a mico keybourd with an ardoino pro micro and nine switches. You can use then as a num pad or as a Strem Deck

The code for the ardoino is open sorce on: https://www.partsnotincluded.com/diy-stream-deck-mini-macro-keyboard/

You need 9 key switches an 9 10k resistors, and dont forgot the soldering ioen :)