Review on Enhance PC Ventilation with SilverStone Technology 140mm Ultra Fine Fan Filter - Compatible with Most 140mm Fans or Vents! by Norlan Pippinmd

They are well made and of good quality. One downside is that the magnets are too weak to hold them in place very well and the holes don't fit into holes where I already have screws holding the fans in place. . However, I use them on the top of my new computer to keep the cables away from the case fans on the top of the computer. So for my needs they work very well, but may not work with side apps.