The EHEIM Carbon Cartridges Liberty are dedicated chemical-filtration inserts tailored for the Liberty hang-on aquariums. These cartridges feature pleated, activated-carbon-impregnated fibre designed to effectively capture dissolved organics, medication residues and other unwanted chemicals while also providing mechanical filtration of fine particles. These carbon cartridges are especially recommended after medication treatments or during initial setup to polish the water and improve clarity. For best results, they should be used for a limited duration (around four weeks) and then replaced to maintain optimal performance.