Keep your water fresh and clean. Protect your appliances by filtering out dirt, sand, silt and particulates. The Evee dual gradient density polypropylene sediment filter fits all 20″ Big Blue Housing and can replace any 4.5″x20″ sediment filter. NSF and ISO certified, it achieves up to 3x the dirt holding capacity of similar size sediment cartridges. When you notice a drop in water pressure or quality, replace the filter every 6 months for optimum results.