24 PACK Pentair C1, 155002-43 Carbon Impregnated Sediment Water Filter Cartridge is the correct replacement carbon-impregnated cellulose water filter for the American Plumber W5CIP. The Pentair C1 cartridge features a tremendous high-dirt holding capacity and captures extra fine dirt, rust, sand and scale particles. The filter's reinforced polyester backing and external netting ensures the filter has additional strength for fewer change outs and greater value. Brand: Pentair