WF-SW2020-BB, NSF certified 4.5-inch x 20-inch String Wound Sediment Water Filter Cartridge by Water Filters Depot (WFD) fits in 20-inch Big Blue (BB) housings of water filtration systems. Our filters provide depth filtration, high dirt holding capacity, extremely low media migration and great micro organizm resistance up to 20 micron. Ideal for food, beverage and other potable water applications as well as variety of commercial and industrial applications. Made with approved materials. Media: Polypropylene Material Center Tube: Polypropylene Recommended replacement time is approximately 4-6 months depends on the quality of the original water source and application type. Micron Rating: 20 Micron. Operating Temprature: 40-150 F-degree (4.4-65.5 C-degree) Available in different packing quantities.