Millex-FA Syringe Filter Unit, 1.0 µm, hydrophobic PTFE, 50 mm, HB-HB. Millex-FA Syringe Filter Unit, 1.0 µm, hydrophobic PTFE, 50 mm, HB-HB. Product Number. Product Description. SDS. SLFA050. A 50 mm diameter non-sterile syringe filter with a 1 µm filter pore size hydrophobic PTFE membrane. The 1 micron filter comes in a pack of 10.