You buy 1000g higher quality filtration ceramic ring bag (500 gx 1 + 500gx 1). Our filtration rings are ideal for aquarium and pelvis filters. These filter rings are packed in mesh bags - they are easily cleaned in the filter. In addition, they can be removed from the bag and placed in the filter. Large surface allowing bacteria to colonize and water to be biologically filtered by the removal of ammonium and Nitrites. Note: You Will Receive Two Mesh Bags, Which Means That The Total Will Be 1000 Grams. Color: White 500g + Red 500g Content: 500 g x 1 + 500gx 1 (net packing). Compatible with: Culture of freshwater nitrate, seawater and grass. Product characteristics: Bacteria can exert great efficiency in the filter. The pore structure can be a good breeding bed to nitrify bacteria, create good water quality and reduce the frequency of water changes.