AMERICAN PLUMBER W5W WOUND Polypropylene Whole House Filter Cartridge 8 Pack American Plumber W5W Wound Polypropylene Whole House Filter Cartridge. Economical & effective. Protects valuable appliances and plumbing fixtures. Ideal for well-water applications. 3-Month filter life or 12,000-gallon capacity. Reduces particles as small as 5 micron in size by mechanical means. Reduces - extra-fine sand, dirt, and silt - Rust and scale particles. Fits w34-Pr and WVC34 filter housings. Also fits Pentair, American Plumber, Pentek Standard and Slim Line, Culligan, 3M/Cuno/Aqua-Pure, Filterite, Keystone Filter, Omnifilter, Watts and most standard size filter housings.