The matrikx + cto2-hd20 water filters are the most widely used carbon block devices in the world and provide previously unattainable performance at the lowest price point. The dirt-holding capacity and the absence of carbon fines makes the kx-matrikx-cto2-hd20 the filter of choice. A superior carbon block combines both high performance and integrity with an exceptional cost-to-performance value. As a result the kx-matrikx-cto2-hd20 virtually renders gac filters obsolete by comparison.