Pre Sediment Filter Cartridge for RO system, under sink and whole house system - 6 Pack Spun polypropylene for resistance to chemicals and bacteria Reduces sand, silt, scale, and rust particles in residential, commercial, and municipal drinking water Combines two separate gradient layers for higher efficiency and dirt-loading capacity Nominal filtration rating of 5 microns Pre-filter for Under-Counter, UV and Reverse Osmosis systems