Ceramic ring filter media Bio Ceramic Rings are a convenient ready-to-use nylon mesh filter bag filled with Ceramic Rings. Surface area and pores sized to accommodate bacteria necessary for biological balance and to remove toxic Ammonia and Nitrite. Helps remove toxic Ammonia and Nitrite. Surface area and pores sized to accommodate bacteria necessary for biological balance. The Bio Ceramic Rings produce crystal clear water and is perfect for use in any canister filter. Net bag included. Quantity 500g of the product as shown in picture one and as written in the subtitle Activated Carbon n essential filter media for every aquarium. Activated carbon is frequently recommended for use in aquarium filters. It can effectively eliminate odors, detoxifies harmful metals, purifies and soften the water absorb chemical residue/ compounds and water purifying effect. The ceramic rings are very porous, although they look solid, there are zillions of tiny holes in it, and that makes it an ideal home for the cycle bacteria that you want in the filter. Ceramic rings are extremely porous, which provides a lot of surface area for beneficial bacteria Due to its cylindrical shape, water flows through it easily and makes it less likely to clog. With fine and porous holes, provide the area for the autoeciousness of nitrifier, with good effect of aeration to provide oxygen for the nitrification good for decomposition of residue. Quantity 500gm Activated carbon of the product as shown in picture one and as written in the subtitle Picture shown for indication propose only actual product color,size may be differ due to camera effect.