This is an adapter to mount a Duet Maestro control board in the Creality Ender 3 enclosure. There are cutouts to help cool the driver chips on the back of the board if you choose to install a fan. There is barely a millimeter of space to spare, but the board does fit. It will require openings to be created in the front of the box. And I suggest a blower fan on TOP of the enclosure mounted flush and pulling air out (not in). This will avoid debris being pulled into the enclosure, and no screen should be needed.I printed mine with PETG for the heat resistance, but annealed HTPLA would probably work, and be stiffer. It's likely the Duet Ethernet would also work, but I don't have the dimensions. I doubt the Duet WiFi is a good fit inside a metal box if you want to get any signal. Without fans running the printer moves almost silently with the Maestro board driving it. The Maestro has even newer stepper chips than the Ethernet and WiFi, but it comes with no installation hardware. And it's a quite a bit cheaper.
I'll add pictures when I have them.
Here is the link to buy the board:
3D Solutech PETG
Found Ender 3 cad file for the metal enclosure, and iterated from there in Fusion 360.