Pleated Big Blue Sediment Reverse Osmosis Filter 4.5" X 20" - If you are looking for a sediment filter that fits 20 inch big blue housing, this is a popular choice. It does an excellent job of water filtration and works on residential/commercial applications. Ideal for removing dirt particles from your water supply. It is also an economical choice as it has a long service life and is reusable once you wash it.