20" PP Sediment Water Filter CartridgeUSAGE Choose your micron rating from 1mic , 5mic , 10mic or 20mic. (lower the micron the lower the sediment size removed , if using multiple stages , start with a higher micron down to a lower micron) Fits all 20" filter housings. Used as first stage in well water filtering, KOI, Aquarium and almost all other water filtering DESCRIPTION 20"PP Sediment Spun Cartridge (For Removal of sediment , dirt,rust,particles). Used as a first filtration stage.