The product is made of medical grade melt-blown ?lter fabric with BFE (bacterial ?ltration ef?ciency) 98% and PFE (particle ?ltration ef?ciency) 96%, which is used to block live bacteria (viable particles) from 1 to 5 microns and micro particles (nonviable particles) from 0.1 micron to 1 micron. Extra protection against smog, bacteria, droplet & pollen. Additonal 1 layer of non woven fabric on the front for better protection.