The Polydisc AS (Aqueous Solution) family of 50 mm filter devices feature a high throughput polyethersulfone membrane, which has low protein binding and no surfactants, developed for use in the pharmaceutical industry. A glass microfiber prefilter extends the life of the membrane and effectively filters heavily contaminated samples. Each Polydisc AS device has a sterility cap on the outlet and is sealed in its own "medical grade" clear blister pack, irradiation sterilized, and secured in a protective shelf pack.