Carbon removes impurities and odors Easy to cut to size of your filter Keeps water clean and clear Our Carbon-Infused Media Pads are great for removing discoloration, toxic waste chemicals, medication, and odors from your aquarium water. When added to your filter, it also helps to polish and clarify the water in your tank. This filter pad works similarly to loose activated carbon media but is much easier to handle and manage. It can easily be be cut down to the size of your filter for a perfect fit. The most common type of chemical filtration is activated carbon, which is a highly porous charcoal that readily absorbs medications, tannins, and other impurities. Activated carbon for aquariums usually comes in loose granules and must be contained in a filter media bag. Our carbon pads are much easier to use, cut to fit, and remove when used up. Our Carbon pads come in a rigid 17.5 inch long and 9.8 inch wide pad. They come folded in half. Also a great secondary polishing pad to remove unwanted waste and particles. To filter out chemicals in a sponge filter tank, simply wrap the carbon pad around the sponge filter and fasten with string, zip tie, or a temporary rubber band. We are often asked "How long do these last?" It depends on the amount of tannins, medication, and pollutants in your aquarium water. The more toxic chemicals and discoloration in the water, the faster it will be exhausted.