A thick prepleated filter paper with high loading capacity. Combines medium retention with medium-fast to quick filtration speed.

• Savings in time required to quadrant-fold circles to fit conical filter funnels in repetitive or multiple analyses
• Decreased overall filtration time because of the extra surface area exposed; the normal slow down of filtration speed due to the loading of particulate is postponed
• Increased total loading capacity as more filter area is available
• Maintained flow rate due to the reduction in filter paper contact with funnel side and the self-supporting shape of the filter itself
• The prepleating does not significantly affect any of the technical data, and the same figures may be used for the flat circles

Time-saving Whatman qualitative grades are offered in this convenient form, which gives major advantages over flat circles.