Check the listing for details. MARINA I25 INTERNAL FILTER REFILL CARTRIDGE - 2 PCS. Condition: New. Listed at 8.99 USD. MARINA I25 INTERNAL FILTER REFILL CARTRIDGE - 2 PCS The Marina i25 Replacement Power Cartridge is specifically designed to be used with the Marina i25 internal filter. It is a 2-pack cartridge that offers mechanical, biological, and chemical filtration for your aquarium. The power cartridge has a polyester foam exterior that effectively traps fine particles and debris. Inside the cartridge, there are chambers that contain carbon, which helps remove pollutants and odors from the water. Additionally, it also contains zeolite, which is responsible for eliminating toxic ammonia, creating a cleaner and healthier environment for your aquarium inhabitants. The combination of these filtration elements helps to ensure crystal-clear water. Replacing the power cartridge is easy and it is recommended to do so every 4 weeks for optimal filtration performance. We will pick best available way to ship Thank you, CountryFishGirl