Nafion HPmembranes are ultra-thin cation exchange membranes that are manufactured by theChemours Company. These membranes are reinforced and designed for lowerrelative humidity environments and high operating temperature. Thereinforcement improves the membranes handling and physical properties. When thereinforcement is combined with the chemically stabilized polymer, the NafionHP membrane exhibits both substantially lower fluoride ion release and longeroperating durability under challenging fuel cell conditions. Nafion HP is 20.3micrometers (0.8 mil) thick. The membrane is positioned between a backing filmand a coversheet.