Grade 1 = 0.003 ppm (0.004 mg/m3) oil removal, active carbon. Grade 5 = 0.008 ppm (0.01 mg/m3) oil removal. Grade 3 = 0.0008 ppm (0.001 mg/m3) oil removal. Grade 9 = 99% bulk water removal. For use in conjunction with all grade filters listed above, for the purpose of odor removal for breathable air.
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