Whatman 1003-240 Quantitative Filter Paper Circles, 6 Micron, 26 s/100mL/sq inch Flow Rate, Grade 3, 240mm Diameter (Pack of 100) 24.0cm Grade 3 Used in qualitative analytical techniques to determine and identify materials Double the thickness of Grade 1; even finer particle retention and excellent loading capacity Extra thickness gives increased wet strength; makes this grade highly suitable for use in Bchner funnels