The fastest ashless filter paper, recommended for analytical procedures involving coarse particles or gelatinous precipitates (e. g. iron or aluminium hydroxides). Also used in quantitative air pollution analysis as a paper tape for impregnation when determining gaseous compounds at high flow rates. The fastest ashless filter paper, recommended for analytical procedures involving coarse particles or gelatinous precipitates (e. g. iron or aluminium hydroxides). Also used in quantitative air pollution analysis as a paper tape for impregnation when determining gaseous compounds at high flow rates.