Merck Millex™-FG Syringe Filter Unit, Hydrophobic PTFE, 0.2 μm Features a hydrophobic Fluoropore™ (PTFE) membrane. Millex™-FG Syringe Filter, 0.20μm, Hydrophobic PTFE provides broad chemical compatibility and is ideal for filtering samples in organic solvents or to prevent back-streaming of atmospheric moisture in venting applications.