Supreme quantitative filter papers featuring fast filtration of coarse particles and gelatinous precipitates in acid/alkali solutions during gravimetric analysis. Hardened ashless: 0.006% ash maximum. These filters are acid-hardened to give high wet strength and chemical resistance with extremely low ash content. The tough surface makes these filters suitable for a wide range of critical filtration procedures. These are the supreme quantitative filter papers featuring high wet strength and chemical resistance. These papers are acid-hardened, which reduces ash to an extremely low level. The tough surfaces pf these fillters make them suitable for a wide range of critical analytical filtration operations. Each grade offers a convenient combination of filtration speed and particle retention. Grade 541: 22 m Fast filtration of coarse particles and gelatinous precipitates in acid/alkali solutions during gravimetric analysis. Typical applications include determining fiber in animal foodstuffs, gelatin in milk and cream, chloride in cement, and chloride and phosphorous in coal and coke.