High efficiency HEPA filter is individually certified to have a minimum efficiency of 99.97% at 0.3 microns (based on D.O.P. tests). For capturing problem particles of dust, pet dander, mold and bacteria, the TEDA vacuum filter media are up to 12 times more efficient than ordinary paper bags, and up to 5 times more effective than lined-paper bags. We also offer the lowest pressure drop or resistance to air flow of any consumer vacuum bags. TEDA vacuum filter media are made of 100% polypropylene fibers that are electrostatically charged to capture small particles. And because particles are trapped throughout the depth or thickness of the material, the media can collect more particles without clogging and reducing air flow.