MCE: Hydrophilic membranes composed of a mixture of inert cellulose nitrate and cellulose acetate. The uniform microporous structure imparts the highest flow rates in terms of membrane filters. PC: Membranes manufactured using the Track Etched technique that yields identical cylindrical pores. This membrane is particularly used in Legionella analysis according to ISO 11731. PES: Hydrophilic membrane manufactured from pure PES polymers. Uniform porous structure.