KX MATRIKX Pb1 10-Inch Length Extruded Carbon Block Filter Cartridge, 3-Pack Matrikx KX PB1 06-250-125-975 features Lead, Cyst and Turbidity Reduction Based on NSF/ANSI Standard 53 Outstanding Chlorine Taste and Odor Reduction Based on NSF/ANSI Standard 42 Graded-density filtration + high dirt holding capacity. Extruded activated carbon provides several times greater life than molded filters. MADE IN USA 0.5 m Nominal Filtration