Materials Polypropylene reinforced PTFE membrane filter. Polypropylene housing Wetting Water penetration pressure, 3.0 bar (300 kPa) for 0.45 µm, 4 bar (400 kPa) for 0.2 µm 11 Minisart®-SRP Syringe Filters with a clean and chemically inert PTFE Membrane Ready-to-use units for simple, rapid and reliable ultracleaning of small