MINIMAL MESS: These cartridges feature a NoDrip design to minimize water mess during changes. POWERFUL CARBON FILTRATION: Each cartridge contains even distribution of activated carbon, which helps remove toxins, odors and discoloration for clearer, healthier water. VALUE PACK: Includes three cartridges for continuous filtration. Ensure optimal performance by replacing the cartridges approximately every 4 weeks. VERSATILE & CONVENIENT: These cartridges have a convenient “FRONT” orientation tab to ensure proper placement every time. Perfect for both freshwater and saltwater aquariums. .