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.
Not just for water cooling. It's for cables that pass in or out too.
Such as?
Edit: I mean you can contrive something if you're MacGyver but there's no remotely standard use case for that.
Anything that doesn't have an external connector or some way to mount one. One example would be if you were using a USB Wi-Fi radio and wanted to connect it to the internal USB connectors but you'd need to pass the antenna to the outside of the case.