Culligan CW5-BBS Heavy Duty Cord Wound Polypropylene Sediment Filter CartridgePolypropylene wound cartridge. Level 4 advanced filtration. Reduces sediment, rust, scale, dirt, coarse sand, sand, fine sand, extra fine sand & silt. Filter life up to 4 months or 16,000 gallons. 5 micron rating. For use with HD 950A. Heavy duty Polypropylene wound cartridge Level 4 advanced filtration Reduces sediment, rust, scale, dirt, coarse sand, sand, fine sand, extra fine sand & silt Filter life up to 4 months or 16,000 gallons 5 micron rating