The Whatman grade GF 9 glass microfiber filter is manufactured with an inorganic binder. For fast filtration of coarse particles. GF 9 is slightly slower than GF 8 but offers a slightly higher retention rate. Frequently used in environmental analysis, for pollution measurements in industrial, urban and suburban areas, cement factories, iron and steel industry, dust measurements at the workplace, determination of the dust fraction in technical gases, or testing the effectiveness of dust-collecting and filter plants. Grade GF 9, circle. Diameter: 90mm. 100/Pack. Whatman #: 10370205.