... -irritating to skin4.Permits air passage and breathable5.In clinical offices, housework, gardening and maintenance for ... filtering dust, pollen, and bacteria6.In laboratories and factories for blocking liquid mists, harmful airborne ... 3-Ply 20gsmPP+20gsm PP+ 25gsm PP2.Dimension:17.5×9.5cm3.Packaging: 50pcs/inboxes 2000pcs/ ... and spot welding,middle ply is filter,blue,17.5*9.5cm