Darlly 20 Inch Hydrophobic PTFE Membrane Micron Pleated 0.1um 0.22um 0.45um 1um Filter Cartridge Overview- ZMFT® PTFE Filter Cartridge (Hydrophobic) F1T Series ZMFT® F1T series filter cartridge is made of Hydrophobic PTFE membrane which has very good resistance to corrosion, therefore it is widely used for the filtration of strong acid, alkali and strong polar organic solvent.