Unsupported pure PTFE membranes offering exceptional resistance to chemical attack. These membranes meet all specifications for performing NIOSH Method 5013. 5µm pore size membranes available in diameters of 37 and 47mm. Typical thickness is 127µm (5 mils). Typical air flow rate is 13Lpm/cm2 at 520mm Hg (10 psi). Available with or without pads.