Penn Plax Pro-Carb Filter Bags for All Canister Filters  Filled with Activated Carbon for Clean Aquarium Water  8 Ounces, 2 Pack Convenient, no-fuss nylon mesh replacement bags for your Cascade Canister filter. Also fits Eheim ECCO, Eheim Pro/Pro II, AquaClear 500 and FilStar Canisters. Includes two, 8 ounce packs. To eliminate the odors and harmful chemicals in your aquarium water; each bag comes filled with Pro-Carb laboratory quality activated carbon. This filter bag will remove chloramines, chlorine, tannins (which color the water) and phenols (odor causing chemicals) and many more. You will see the difference in water quality almost immediately. Bags measure 8x4 inches and are perfectly cut to fit into the filter tray without any gaps. You will never have to worry about the water getting through the gaps and not being filtered. For best results rinse the carbon filter under cold water thoroughly. This will help remove any loose carbon particles that are in the bag.