What are the rubber circles for on the back of my pc case? Should I just leave them like that if don't have a need for them? Or are they likely to let I'm dust into the motherboard?
Edit: thanks for all the replies, so just for water cooling I have no need for.
It is probably an old case design. In the early water cooling days, there would be separate watercooling units that sat outside the case. The grommets were so you could pass your tubing through.
I wouldn't really worry about the dust tbh, you will wind up having to clean it regardless.
This is it! Old water coolers
Specifically, these are for being able to pass in the tubing when your computer overheats playing Counter-Strike 1.5 so you pull apart your 50cc moped so you can bolt the moped radiator to the side of the case since it doesn’t fit inside. At least that’s the only use I’ve actually seen in practice.