Designed for Ender3v2 to mount behind the LCD screen. I would imagine this works with other Ender 3s but I cannot confirm
You'll want to use supports for the rails
If you're looking for a mount to go in middle to replace the drawer, see here: https://www.printables.com/model/579503-raspberry-pi-4-mount-for-ender-3-v2-drawer-replace
Update (09/11/2023): based on some feedback, I have redesigned the rails (using a new extrusion template that I've used on a couple other designs that works great for me) and I have also increased the port tolerance from 0.5mm to 1.0mm. I have also included the fusion project file as well if you want to edit the hole_tolerance parameter
Note: Originally, I designed this to have studs that the board slides over, but those proved unusable because the ports needs to slide into the holes on the side of the case. So, I removed the studs and countersunk 2.5mm holes for use with M3 screws. I have not tested this, but I don't see why it wouldn't work this time around. I ended up having to just cut the studs off of my printed model and then I wedged a piece of paper in there to hold it in place. With the screws, this shouldn't be necessary -- or you can do that if you don't want to use screws
Oh, and this is the fan I'm using: Argon Mini https://www.amazon.com/gp/product/B08HLX9WRV/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1
The author marked this model as their own original creation. Imported from Thingiverse.