equivalent to Whatman/Schleicher Schüll article No. 1440240. Basis weight: 85 g/m2. Thickness: 0.2 mm. Filtration speed: 55 s/10 ml. Smooth. Ashless, medium rate of filtration, for example, for magnesium ammonium phosphate, zinc sulfide, etc. MN 640 md is an ashless filter paper, which is slightly more retentive than MN 640 m with corresponding increase in filtration time.Meer tonenMinder tonen