KX MATRIKX CTO filters are optimized for applications where they perform the role of both a sediment and activated carbon filter for chlorine taste and odor reduction. These filters are known industry-wide for superior performance. 5 Micron Nominal Filtration Rating (10 Micron Absolute Filtration Rating). KX MATRIKX 32-450-20-MATRIKX is the factory recommended direct replacement for 32-450-20-GREEN and 32-425-125-20, which have both been discontinued by the manfuacturer. MATRIKX CTO CARBON BLOCK FILTERS ARE NOW RATED FOR CLORAMINE REDUCTION. Chlorine and Chloramine Reduction 5 micron nominal filtration reduces sand, rust, and sediment. Exceptionally low pressure drop. High dirt holding capacity. Excellent chemical contaminant reduction. High Adsorptive Capacity and Efficiency. NSF and WQA certification for Material Safety. 100% Coconut Shell Activated Carbon Performance validated by independent laboratories Manufactured in an ISO 9001 14001 certified facility Certified for Sustainability by WQA - S-803 California Prop. 65 Compliant. Industry-Standard Size for Universal Replacement. Fits #20 Big Blue (20"BB)