Grade 301 is the slowest of the qualitative papers. This grade is used in qualitative analytical techniques to determine and identify materials. It is also extremely efficient in retaining very fine particles. Grade 301 is generally used for biological products, water analysis, soil analysis and fine precipitates such as cold precipitated barium sulfate. Grade 301 is additionally utilized with Buchner funnels and to clarify cloudy suspensions and wine.

Grade 302 is a thick smooth paper, suitable for the removal of fine particles. This paper is made with 100% pure cellulose fibres that have been strengthened to resist the pressure when they are used in filter press systems. There is therefore no contamination danger during transfer steps. This high absorbency grade is twice as thick as Grade 301 with a bigger pore size. The extra thickness gives higher wet strength and loading capacity, enabling more precipitate to be held without clogging the filters and better handling. Grade 302 is also highly suitable for use in Buchner funnels and dye filtration.

This grade is used for the filtration of coarse particles and gelatinous precipitates such as ferric aluminum and magnesium hydroxides. Grade 305 is used in air monitoring and gas filtration when high flow rate is needed. This grade is also found in routine cleanup analysis of insoluble liquids such as biological fluids and organic elements.