First and foremost - Thank you Michael ( Teaching Tech ) for creating this awesome solution to move electronics to the back of the Ender 3 printer. This design is incredible.
Many people expressed concerns about heat - and some people remixed to address.
Original Lid remix by LUIGITIME9 (https://www.thingiverse.com/thing:3813999) inspired me.
Personally, I felt the lid was too thin, and the fans in other designs were not located close enough to the X / Y drivers.
The included SKR / MKS Gen L (RIGHT) CASE design is not mine.Designed by Carlthingiverse.( https://www.thingiverse.com/thing:3822712 )
I remixed the TOP only, thickening it, and adding/relocating the dual fans.
4 x M3x16mm (or 8 if you prefer)
4 x M3 Nuts
The M3 bolts should be threaded into the top from the bottom, and I preferred to hot-glue to hold in place and ensure against possible electrical shorts. I have the SKR v1.3 with TMC2208's (v3.0) with the tall blue heatsinks - the bolts are no-where near this configuration - but safety first right?
The right hand side fan (nearest the Z screw) can be attached prior to installation.
The inner fan must be attached to the top after insertion. Just use a pair of needle-nose pliers to snug up - no need to over tighten.