This is a two port USB extension bracket for mounting under a desk or table.  It was designed for Amazon Basics USB extension cables but might fit other brands.  

It was designed to use 4 screws for mounting.  The screw holes have a diameter of 4mm.  I used self-drilling screws to mount mine.  If you don't wish to use screws some good two-sided tape might work as well.

When I printed mine, I used some modifiers to beef up the infill for the section where the screws go through to give it some strength, I've included a .3mf file that has the modifiers already positioned.

If you have tuned bridge settings this will print without needing supports.