Compatible Replacement: This 20 x 4.5 whole house iron and manganese water filter fits most 20 inch water filter housings. High Quality Filtration: The high capacity water filter is able to improve water quality at a flow rate of 4.5 GPM, reducing Iron and Manganese levels to 0.01 ppm. Most effective in water with no more than 3 ppm Iron. 6 Month Filter Life: Depending on the quality of your water, replacing your home water filter cartridge every 6 months is recommended for the average household to ensure optimal performance. Durable Materials and Design: Tier1 products undergo strict quality assurance testing and are manufactured using the highest quality materials. Quick & Easy Installation: Simple and easy universal fit into your 20 x 4.5 Inch whole house water filter system.