Grade GF/A: Offers fine particle retention and high flow rate, as well as good loading capacity. Used for high-efficiency general purpose laboratory filtration, including water pollution monitoring of effluents, for filtration of water, algae and bacteria cultures, foodstuff analyses, protein filtration and radioimmunoassay of weak ß emitters. Recommended for gravimetric determination of airborne particulates, stack sampling and absorption methods of air pollution monitoring. This filter is also available in the FilterCup and Disposable Filter Funnel formats. Properties: fast, high loading, Particle retention in liquid (µm): 1.6. Particle retention rating at 98 percent efficiency. Filtration speed herzberg (s): 62. Basis weight (g/m sq): 53.