Amazon.com: HFEIX 120MM PC Fan Dust Filter Computer Case Fan Magnetic Frame Dust Filter Fine PVC Mesh Length 4.72 x 4.72 inches Black-4Pack : Electronics
Test: Nylon vs. plastic dust filter. Which restricts fans less? - HWCooling.net
Premium Dust Filter Material 50cm x 40cm x 5mm - modDIY.com