This is a simple enclosure (without a lid, at least for now) for the TOFU carrier board for the Raspberry Pi Compute Module 4.

It is built with access to all the standard ports except for the SIM tray. I presume if you're going to be swapping out the SIM card, you might also be pulling out the board to manage the M.2 slot underneath (e.g. to put in a 4G LTE card).

The standoffs hold the board up just enough to keep the M.2 card from touching the bottom, and there are some ventilation holes on the bottom which will provide a little convective airflow if you put bumpers on the bottom of the case.

The standoffs are meant to be used with M3 press-fit screw retainers. I used some cheap ones I found on Amazon. You push them in with a soldering iron, they melt into place, and then you can secure the TOFU board into the case with any standard M3 screw.