This box houses the adafruit USB isolator board from here: https://www.adafruit.com/product/2107
It features logos, cooling vents and a seamless design which clips nicely into place. No screws needed.
I included the design file, please note that the case without vents misses the keep-out for the "V_out" SMD LED and resistor. You have to cut some material away there if you want to use the non-vented variant. The vented design and the .STL files are already fixed.