Hydrophobic PTFE Supported Membranes manufactured by ADVANTEC MFS, Inc. are supported by way of a polypropylene net laminated to the underside to improve handling characteristics. PTFE Supported Membranes are inert to most chemically aggressive solvents, strong acids and bases. PTFE membrane is manufactured in a unique way where polytetrafluorethylene (PTFE) is expanded both uniaxially and biaxially. The resultant membrane is thin, highly porous, and behaves as an absolute retentive membrane.