The Aqua Culture Filter Cartridges Model L is a 3-pack designed for use in 20-55 gallon aquariums. These filter cartridges, made by Aqua Culture, are essential for maintaining the water quality in fish tanks. With a country of origin in China, these cartridges are reliable and efficient in trapping impurities and waste to provide a clean and healthy environment for your aquatic pets. Ideal for regular use in aquariums, these filter cartridges help in keeping the water clear and suitable for fish to thrive.