Target2 PTFE Syringe Filters are used for general biological filtration. They are especially well-suited for applications where high protein recovery is desired. Target Polypropylene Syringe Filter Housings Meet The Requirements of 21 CFR 177.1520. Target 2 PTFE (Hydrophobic) Syringe Filter 0.2 µm, 17 mm, 100 Pk.