STERILE Pall Supor Membrane Filter, 47mm, 0.2 um, Gridded, Pk of 200 Ideal for biological, pharmaceutical, and sterilizing filtration requirements. Supor® hydrophilic polyethersulfone membranes offer higher fluid flow rates, lower protein binding, lower extractables, and greater strength than other cellulosic (acetate, nitrate) membranes.