The Corsair and Fractal cases I've had/have come with filters that use this fine nylon mesh. I see the same material used as pre-filters for air cleaners. The stuff you can easily get online for PC ...

Designed for industrial applications such as outside plant air-intake systems, custom metal-mesh air filters and screens keep dust and bugs out of equipment and critical cooling systems, and can be ...

The PC Racing Flo Oil Filter is a beautifully machined billet aluminum case with a reusable stainless mesh filter. The filter is claimed to have 200% more filter capacity than disposable media types ...