... pleated filter cartridges, also by all kinds of treatment: PTFE coating, PTFE membrane, water & oil proof, and antistatic by aluminum foil ... BIA-Test certificate. ItemWeight (g/m2)Thickness ( mm)Air Permeability (l/m2.s)StrengthWorking Temperature ()Filter Glass (ASHARE52.2 ... air permeability is under P=200Pa.2.Testing of material for efficiency is 325mesh talcum powder. (JB/T 10341-2002) PTFE Membrane ...