The file 'DC Barrel Jack Bracket5.5 X 2.1 16 3D Printer Model' is (STL) file type, size is 142.8KB.
How a hollow bushing connects, and the holder is produced can be seen below:
https://nerd-corner.com/using-a-barrel-jack-as-a-switch/
or
https://nerd-corner.com/de/hohlbuchse-als-schalter-verwenden/
BuchsenhalterSW22.STL | 182.3KB | |
Halter16.STL | 347.7KB |