- Large Filter Cartridge for Top Fin: 8 Pack RFL Replacement Filter Cartridge designed for Top Fin Desktop Aquariums featuring a Large Retreat Filter. Dimensions: 7.48 x 2.67 inches. - Efficient Water Purification: Each cartridge includes double high-density cotton, activated carbon, and zeolite filter media. The double high-density cotton effectively filters out impurities and debris. The activated carbon absorbs 99% of debris and odors, while zeolite removes heavy metals and helps to balance pH levels. - Advanced Zeolite Filter Medium: Our reprocessed spherical zeolite offers superior cleaning power, efficiently adsorbing heavy metals and harmful substances. It stabilizes pH, enhancing the effectiveness of fertilizers for aquatic plants. - Easy Installation: Simply turn off the filter, remove the used cartridge, and rinse it under water to eliminate dust. After rinsing, insert the new cartridge into the flushing chamber, ensuring a secure fit. - Ideal Use Scenarios: 1. Perfect for maintaining a clean and healthy environment in small desktop aquariums, ensuring optimal water quality for fish and plants. 2. Essential for aquatic plant enthusiasts looking to enhance growth and nutrient absorption through improved water conditions. 3. Suitable for busy aquarium owners needing a hassle-free maintenance solution with quick installation and replacement. This product combines high-quality materials and innovative design to provide effective and reliable water filtration for your aquarium.