Micro Filtration2-Ply Filtration System99.7% FiltrationCaptures Microscopic Particles AllergensA Must for Allergy Sufferers!Micro-Filtrationvacuum bags filter 99.7% efficient down to5.0 microns and can capture particles as small as 0.1 micron.What is a Dust Window?Dust Windows are clear plastic liners on the bag. This allows users to see how much dust is in the bag.Never over fill or under fill your bag again! New Item: New Items Have Never Been Used.These Items Are Still Covered Under Our Return Policy.