My casing cm690II advanced have some holes at the side. One side is clear plastic, one side is metal. I did not have any side panel fans.
I want to buy two dust filter and attach to it on each side. How to attach to it?
You use the same screws you use to mount the fan. The screws would first go through the filter, then the case, then the fan. You most likely will need longer screws. If so, you can get #6 pan head sheet metal screws from a hardware store or Home Center. I would suggest cutting, grinding, or filing off the sharp tips of the screws (leave most of the end taper, though) to avoid possible injury when handling the case side but it isn't necessary to do so.
If you aren't going to install a fan behind the filter, you can use 6-32 machine screws, washers, and nuts. Depending on how many washers you use, 1/4" or 5/16" will probably be long enough.
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