Nalgene Syringe Filters, PES, 0.2um, Sterile, Box 50
More info. Nalgene Syringe Filters, PES, 0.2um, Sterile, Box 50. Nalgene® syringe filters with PES (polyethersulfone) membrane are specially designed to sterilize small volumes of aqueous liquids using a syringe. PES membranes offer lower protein binding, lower extractables, no wetting agents and higher flow rates than cellulosic membranes.