PP Spun Filter Cartridges are made up of 100% pure polypropylene fibers FIlter Cartridges. Sediment 5 Micron up to 50 Micron Water Filter Cartridges remove algae, dirt, particulate matter, rust, sand, sediment and silt. Aqua Best Water Filter Cartridges are suitable for use in domestic, commercial and industrial applications. Great and efficient water filtration.