Compatible Replacement: This 25 Micron 20 x 4.5 granular activated carbon water filter is a replacement for Pentek RFC-20BB, SDP-4520, 155247-43 and fits most 20 inch water filter housings High Quality Filtration: The high capacity radial flow granular activated carbon filter is able to achieve filtration down to 25 microns improving taste, odor, and water quality, at a flow rate of 4 GPM, reducing chlorine taste & odor, sediment, dirt, and particles 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