GR615 Filter Paper Circles. 100 Circles/PK. 100PK/CS. 9.00cm diameter circles. Qualitative, High Purity Filter Paper. Fast filtration speed/abs. Weight 70g/m2, Thickness 0.26mm, Herzberg 29sec/100ml, Rapidity 235ml/min, Capillary Rise 32mm, Retention 25um, Creped surface, 70% cotton/30% wood fiber.