50mm 0.22um Hydrophobic PTFE air Vent Filter for Vacuum Pump 50MM PTFE INLET SYRINGE FILTER: 50mm 0.22um or 0.45um PTFE Inlet Syringe Filters, Hydrophobic PTFE membrane is laminated with polypropylene. 50MM PTFE MAIN APPLICATION: Naturally hydrophobic PTFE membrane provides the best chemical resistance, and can be used forventing applications or filtering gases , individually wrapped filters.