The Pentair Pentek CBC20-BB is a high-capacity carbon block cartridge designed for Big Blue whole house water filtration systems. Its bonded powdered activated carbon (PAC) media provides over 150,000 gallons of chlorine taste and odor reduction at a 4 gpm flow rate, while the 0.5-micron rating captures fine sediment and particulates that coarser filters leave behind. The result is cleaner, better-tasting water from every tap in your home.Built with polypropylene endcaps, polyolefin wrapping, polyethylene netting, and Santoprene gaskets, the CBC20-BB meets NSF/ANSI Standard 42 material requirements for safe drinking water contact. The cartridge operates in water temperatures from 40 to 180 degrees F, making it suitable for both residential and light commercial applications.Each cartridge measures 4.625" x 20" and fits standard Big Blue 20" x 4.5" filter housings. This 4-pack keeps replacements on hand so you can maintain consistent water quality without interruption.