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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.
Dust will get in pretty much no matter what you do. I wouldn't worry about it. If you live in an already really dusty environment then get some sections of filter and attach them inside of these holes but honestly I wouldn't worry.
It's for water cooling loops if you want to mount the rad or pump or something outside of the case. I think it was more common in the early days of water cooling when things were less standardized.
Not less standardized so much as when the only cooling loops were custom ones and not AIO