Fluval C3 Carbon -12 Filters Total (4 Packs with 3 Filters per Pack) 12 Fluval C3 Carbon Filters Total (4 Packs with 3 Filters per Pack) Replacement media for the Fluval C3 Power Filter; For freshwater or marine environments Absorbs impurities that lead to discoloration and odor Improves water clarity Works to provide your fish with a healthy aquatic environment