Marina T100 Replacement Aquarium Filter Cartridges are for use with all Marina 3.7 L (1 US Gal.) aquariums, including the Marina Pirate Aquarium Kit and the Marina Mermaid Aquarium Kit. Marina Replacement Aquarium Filter Cartridges remove pollutants and odors, and improve water clarity and color. Key Features :For use with all Marina 3.7 L (1 US Gal) Aquarium, including Marina Pirate Aquarium Kit (13310) and Marina Mermaid Aquarium Kit (13311). Improves water clarity and color. Removes pollutants and odors.,