Breathe Freely ePTFE Membrane Mask Better than N95 Filtration Efficiency Effective 0.075 microns >99.7%. Pore size 0.2 microns, 8 Billion Pores, 99% Consistency ePTFE (Poly Tetra Fluoro Ethylene) film. Select Type Select Package Size 30 pcs/box, 32 box/carton Add Inquiry