A fast filter paper with high wet strength. It has a very smooth surface making it easy to scrape or wash off precipitate. These extremely strong filter papers have a high wet strength due to the addition of a small quantity of chemically stable resin. Normal qualitative applications will not introduce any significant impurities into the filtrate. The resins do, however, contain nitrogen so these grades should not be used in Kjeldahl estimations, etc. Resistant against: sulfuric and nitric acid solutions (up to 40% at 50°C); hydrochloric (up to 10% at 100°C, 20% at 60°C, 25% at 20°C); and alkalis (up to 10% at 20°C).