The AquaCera 9" CeraGrav Plus Filter W9511250 is a ceramic filter cartridge. It is a highly efficient filter that combines coconut shell carbons, a granular activated carbon core, and the filtration qualities of ceramic carbon. Coconut carbon is effective in the treatment of chlorine, taste and odor. The filter is silver impregnated to prevent the growth of bacteria, is self-sterilizing and the filter elements are cleanable. The filter purifies water up to a micron rating of 0.5. To get the best results from the filter for safe, fresh water, use it with a gravity water filter. The filter has a rate of 1 gph and purifies water by removing heavy sediments, organics, rust, sand, and silt.