Why are there dust filters on exhaust fans?
Dust filters should be installed on intake fans,
and fans in the top panel should be exhaust fans --
to assist the "stack effect" (hot air rises).
-OR- is the original post referring to the mesh grill
that forms the top panel?http://www.coolermaster.com/product.php?product_id=6638
See also Rodney's excellent video review here:http://www.3dgameman.com/reviews/1126/cooler-master-690-ii-advanced-case