Unicel (K-40630-B) 20" x 4.5" Pleated Polypropylene 10 Micron Sediment FilterUnicel K 40630 B 20" x 4. 5" Pleated Polypropylene 10 Micron Sediment Filter Reusable pleated cartridge for Big Blue housings with extended surface area and simple garden hose cleaning 10 Micron Pleated Polypropylene Made in USA Reusable WHY IT WORKS Pleated design means more filtration surface and longer service life Reusable Construction Pleated polyester cloth can be cleaned and reused multiple times. When flow slows, rinse with a garden hose and