Ahlstrom6170-2050 Qualitative Filter Paper, 20.5cm Diameter, 35 Micron, Fast Flow, Grade 617 (Pack of 50)

I bought this paper to filter my various chemical solutions that are required for Wet Collodion Photography. The filters fold nicely into my funnels and do a good job of trapping very fine particulant matter. Fast flow is relative (or I guess their may be a specification for this). The flow is not that fast as when I was using several coffee filters, but this product does a much better job. The quantity of filters in the box is much more than 17, that part I don't get.