GEs thinnest Whatman brand hardened filter paper, highly glazed Grade 50 supports vacuum filtration in Bchner funnels or Hirsch funnels and enables strong retention of very fine crystalline precipitates. -Thinner filter design (average thickness 115 m) than most Bchner filter papers -Acid-treated for high wet-strength and chemical resistance -Nominal particle retention of 2.7 m -Slow flow rates (Herzberg filtration speed 2685 s) -High purity and low ash content (0.015% ash maximum) -Compatible with Hirsch or Bchner funnels GE offers three grades of hardened low ash filters For many vacuum filtration applications, a thin filter paper with a slow flow rate and excellent wet strength can maintain sample quality and purity. Because Grade 50 thin filter papers are hardened to minimize fiber shredding, they are a good choice for use as carriers in integrated circuits. Wet-strengthened filters for vacuum filtration. Grade 50 thin filter paper from GE Healthcares Life Sciences business is very strong when wet. It will withstand wet handling and precipitate removal by scraping. All three are designed for use in Hirsch and Bchner funnel applications and can be customized for an exact fit.