Cytiva's Whatman Grade GF/D fine membrane filters are thick and offer good loading capacity. GF/D can also function as a prefilter when used with GF/B, and it comes in many sizes to fit most filter holders. Thick filter media for increased loading capacity Nominal particle retention of 2.7 µm Can be used as a fine membrane prefilter Cytiva offers glass microfiber filters with a range of pore sizes and thicknesses. Browse other binder-free Whatman glass filters to find the right filters for your needs. Fine membrane prefilter benefits Whatman Grade GF/D from Cytiva's business is a membrane prefilter that provides protection for membranes with fine retention. The filter can be used with Whatman Grade GF/B filters to provide efficient membrane protection, especially during liquid scintillation counting.