Newmarket Naturals April Shower Replacement Filter Cartridge, SLC-APSLC, for AXDO, TROP, MON, and OXYD Shower Filter Replacement Cartridge SLC-APSLC lasts 4 to 6 months or 7,000 gallons. Flow Rate: 2.5 GPM. Removes 98.9% chlorine, NSF tested for chlorine removal, standard #177 Removes 98.9% chlorine, NSF tested for chlorine removal, standard #177