... sewing , welding, w/o antifog plastic, single or double noseLayer: 1ply, 2 ply, 3ply, 4plyMaterial: PPSB 25gsm, Melt blown 20gsm,, PPSB ... 20gsm Ear-loop type: 3-ply polypropylene cloth, low breathing resistance and high filtration efficiency.Mini ... while outer cover is water resistant.Tie-on type: 3-ply polypropylene cloth, low breathing resistance and high filtration efficiency. ...