Reach for the Pentair Pentek GAC-BB Big Blue Granular Activated Carbon Taste & Odor Filter when it s time to change the filter in your 10 heavy duty whole house water filtration system. This filter is designed to allow maximum contact between the water and carbon ensuring optimal adsorption. The construction of the cartridge allows water to enter at one end and pass through the entire length of the carbon bed before exiting the other end of the cartridge while an internal expansion pad minimizes channeling or bypass. Before the water exits the cartridge a post-filter helps reduce carbon fines and other suspended particles from the filtered water. The post-filter is permanently fastened to an innovative support basket ensuring that it is firmly secured and eliminating any potential for bypass.