BRIEFCEC Dust Filter 120mm for Computer Cooler Fan/PSU/Routers NYLON 80 Mesh, Magnetic Frame PC Fan Dust Mesh PC Cooler Filter Dustproof Computer Fan Grills (NYLON, 4Pack, Black)

Bought these based on price - the 4 pack, delivered next day by 1pm for £9 seemed better than the alternatives.They are much finer mesh than I expected, and I think they're going to do a better job as a result.

The mesh is not stretched/fasten enough, so the fans may suck & hit the mesh when spinning, making a little noise.

I had airflow problems with my case and bought a cheap mesh fronted case to replace it. This worked well for my PC cooling but it came with absolutely no filter for the front 3 x 120mm fans. This case is on my desk but had it been on the floor that would have hoovered up a manner of fluff and fur within a few days.I looked at improvising or 3d printing something myself but saw these purpose made filters instead, and for the price they were a better bet. They seemed OK quality and the mesh is very fine so good enough to stop the dust.I fitted them using only magnets at first but it was obvious they would not hold for long even on the solid metal frame. The slightest knock or even the fan vibration would've make them drop out of position and then I'd be constantly unscrewing the case etc...So I started screwing one of them and ended up putting some screws in all of them. Now it could be my cheap case but the alignment of the holes means they buckle and lift slightly allowing air down the sides etc.In practice this hasn't caused many issues and they are doing their job and keeping the dust out, but if the magnets had been stronger I probably wouldn't have had to use the screws.

Sizing was very accurate; this was important to me, since they need to slot into pockets I've custom-made to suit them. The airflow seems as uninterrupted as I could hope for, since you can blow on one side and feel exactly the same pressure on the other side with your hand, as if it wasn't there. This must be because the mesh structure is absolutely tiny; both the 'wires' and the gaps between them. Superb. Bought lots more since, for custom media cabinet cooling solution together with Noctua fans.

The mesh is small enough and the magnets strong enough.

I was fearful that they would just drop off the case because of people complaining that the magnets were not strong enough. I have had absolutely no problems at all in this regard. They stay on fine, and my PC case is just a very average steel case.If you want an ultra-fine fan filter, then these are the best value one’s going (£8.99 for 4 x 140mm).Also the filter mesh is perfect as far as I am concerned and should stop nearly all dust but still lets air pass pretty well.I have now purchased an additional four of them.

Does the job of catching dust. No complaints.Still allows air to flow in .

The magnets on these are pretty weak. They work fine on a solid case, but don't expect them to stick to a mesh panel as is so common on today's PCs.