Marineland Rite-Size Cartridge C, 6-Pack Go to amazon.com Related posts Top recommendation for aquarium filter cartridge FeatureRite-Size C filter cartridgeMeets the highest standards of water purification and operational easeEach cartridge is pre-assembledA perfect fit for every filter. DescriptionReplacement Cartridge for Penguin 170, 200, 330 & 350 Filters