This is a Nintendo Switch dock casing designed with both portability and functionality in mind.
It makes the dock portable while keeping important features, like the spring-loaded connector that keeps your Nintendo Switch charging port safe. It also has an indent for a felt pad that keeps your Switch safe from scratches!
If you want to print and assemble one, you will need a small flathead screwdriver to take apart the original dock, a couple of M3 screws for the stand, and a felt pad. You can find adhesive backed felt for cheap pretty much anywhere online.
Here's a youtube video about the dock: https://www.youtube.com/watch?v=nZ3YOfx6whU
Please let me know if you have questions or suggestions. :)