Black filters for my computer

[Synthetic-Pulse]

I am looking for some filters that I can put into the vents on two of my computer cases, I live near a busy road and it gets very dusty in my room. I would prefer that they are black and are at least 2 feet long. Thanks for the help.

[PlayModeOn]

On eBay search up fan filters, most of them are only $1-3, black and sturdy.

I got three of these http://www.ebay.com.au/itm/131347794571?_trksid=p2060353.m2749.l2649&ssPageName=STRK%3AMEBIDX%3AIT 

They look better in person and they are surprisingly well-made, I thought at first they are just cheap, flimsy plastic.

 

If you want better filters, search up Silverstone fan filters, they have different versions and colours.