Crystal Quest CQE-RC-04010 Iron Filter Cartridge Capacity: 2,500 gals (3 ppm); 4,000 gals. (2 ppm); 8,000 gals (1 ppm) Up to 3 ppm of dissolved iron Cartridge will fit 10x2.5 standard housings It reduces the possibility of damage to pipes and water heaters It helps eliminate orange and brown stains in sinks, tubs and other plumbing features