7100448 - 5 Micron Premium Carbon Block Filter Cartridge 9-3/4"Watts 7100448 5 Micron Premium Carbon Block Filter Cartridge 9 3 4" The 10 inch Full Flow 5 nominal micron carbon block uses top of the line coconut shell carbon. This low cost carbon block filter outperforms granular activated carbon cartridges in chlorine reduction, lower pressure drop, lower cost and offers no water channeling. It offers a long life of up to 20,000 gallons at 2 gallons per minute flow rate. Features 5 Microns nominal rating 100