Katadyn Ceradyn Replacement Filter Element Ceramic body Microporous silver-impregnated ceramic Filter filling is composed of silvered quartz pebbles Provides fresh and natural tasting drinking water Each replacement filter element has a silver rock core which prohibits bacteria growth and elongates the life of the filter element Cleanable silver impregnated ceramic filter element last up to 13,000 gallons Replacement filter element includes measuring gauge to indicate when to replace