The Pentair Pentek C1-20BB is a dual-purpose replacement cartridge for 20-inch Big Blue filter housings, combining sediment filtration and chlorine taste and odor reduction in a single filter. Built with powdered activated carbon (PAC) impregnated cellulose media and nominally rated at 5 microns, it captures fine particulates while reducing chlorine for cleaner, better-tasting water throughout your home.With a chlorine reduction capacity of over 40,000 gallons at 4 gpm, the C1-20BB delivers long filter life and low operating cost. The polyethylene outer netting provides additional dirt-holding capacity and structural support, while the polypropylene core keeps pressure drop to just 2 psi at 4 gpm. Operating temperature range is 40-125 degrees F.IMPORTANT: The C1-20BB uses cellulose-based media and is designed for use with chlorinated water supplies only. Cellulose media is susceptible to bacterial attack in non-chlorinated water. This cartridge is NSF/ANSI Standard 42 certified for material safety requirements. Fits all standard 20" x 4.5" Big Blue and heavy-duty filter housings.