http://www.sigmaaldrich.com/catalog/search?term=NAFION+MEMBRANE&interface=All&N=0&mode=match%20partialmax&lang=en®ion=GR&focus=product Nafion® perfluorinated membrane - Nafion® 117, thickness 0.007in. - Nafion® 424, reinforced with poly(tetrafluoroethylene) fiber, thickness 0.013in.(Aldrich)