Replace the PBS-400 cartridge (EV9270-86) yearly to reduce the following contaminants: Lead to below the Federal Action Level of 15 ppbCysts such as Giardia lamblia, Entamoeba histolytica and Cryptosporidium parvum And the following substances: Chlorine taste and odorDirt and cloudinessMold and algaeOxidized ironOxidized manganeseOxidized sulfidesParticles 1/2 micron and larger in sizeLimescale build-up in appliances that use water