This is to magnetically mount the M5Stack NanoC6.  It is designed for 6mm x 2mm magnets.  

I include STEP and Fusion 360 files for easy remixing.

Features:

• Nice friction fit; arms are slightly tapered so they flex a little and maintain grip
• Front facing button + LED
• Reversible: works equally well with the USB-C or Grove connector facing up or down
• You can install / remove the NanoC6 without unplugging any cables.
• Does not block connectors or ventilation slots
• Strong part (sensible layer lines), no supports needed.

Tips:

• Print on its base - same orientation as the photos - not on its back.
• Use a drop of CA glue to secure the magnet

What do I use this for?

I have a NanoC6 loaded with ESPHome firmware controlling a Mitsubishi Heat Pump (I started with this guide).  Some heat pumps are wall mounted and the NanoC6 (or other ESP32) sits inside the units plastic enclosure.  I have a larger ducted unit with a metal enclosure.  The NanoC6 needs to sit outside the metal enclosure to get a Wifi signal, and this simple magnetic mount keeps it neatly in place.