Filter paper is highly retentive, and is relatively slow. Used for filtering fine crystalline precipitates of less than 2.7 µm. 250 seconds is initial filtration speed. Normal loading capacity. Surface is free of loose fibers, hard, smooth and highly-glazed. Resistant to chemicals and has high strength when wet. For filtering biological solutions. Ash content is 0.30 mg per 12.5 cm circle. (For cost savings, see Ahlstrom equivalent, 445-900-02 Series)