The qualitative filter papers are manufactured from pure cellulose with a proportion of alpha-cellulose of almost 100 %. The ash content is about 0.06 %.

Grade 2025, slow filtering, particle retention 3-5 µm, filtration speed 100 s according to DIN 53137, basis weight 84 g/m², thickness 0.15 mm

For precipitation such as zinc, nickel and tin sulphide, calcium fluoride and calcium hydroxide.