NTnormal 10 Piece, Activated Charcoal Carbon in Free Mesh Media Bags for Aquarium Fish Pond Canister Filter Bags, 10 lb. Removes odor, colors organic pollutants, removes toxic compounds, medications Fast working, long lasting, keeps water crystal clear, phosphate free, safe for freshwater and marine aquarium Media bags allow the precise placement of carbon and ensure granular media doesn't travel through pumps and pipes The zipper-design media bag is reusable., Size of filter media bag: 8 " x 5.5 " As with all carbon, rinse carbon fines before use