GR642 Filter Paper Circles. 100 Circles/PK. 100PK/CS. 12.50cm diameter circles. Qualitative, High Purity Filter Paper. Medium filtration speed/abs. Weight 95g/m2, Thickness 0.20mm, Herzberg 229sec/100ml, Rapidity 30ml/min, Capillary Rise 18mm, Retention 2um, Smooth surface, 100% cotton fiber.