Like the title says, this is to cover up the gaping hole at the backside next to the PCIe slots that is in the original design of the Cooler Master Qube 500 Flatpack.
It is actually a bit of a flaw in the otherwise pretty perfect Qube 500. It's the only gaping hole in the case. With this cover, no dust or large objects can penetrate into your case, keeping it safe and clean.
Cover snaps into place from the outside. Sort of twist and mount it from the top to get the little side supports in. Then it folds right down into the entire slot. See pictures for the example.
Printed in white PETG without supports on a mini+. Normal settings, took about 30 mins. No special requirements.
The author marked this model as their own original creation.