What is porous filter technology? Two proprietary technologies create porous polyurethane material (open microscopic holes). These technologies enable high performance filtration. 1. Cell control technology Controls the cells that make up the polyurethane material so that they form the ideal density and size for trapping pollen-sized particles. In addition, using a 3-D mesh structure allows 99% of pollen to be blocked*. 2. Technology to remove polyurethane's characteristic membrane Complete removal of membrane inhibiting air permeability (cell membrane). This makes possible incredible air permeability not normally seen in polyurethane material. How to use] In order to block pollen, please wear the mask in the correct orientation. 1.Orient the mask vertically, check that top part comes on top, then open horizontally. 2.Pull the ear straps back over both ears. 3.Press down lightly on the mask to make sure it fits without any gaps.