Strong Compatibility: The code number of our aquarium filter cartridge is S, and the specific size is 3.75 x 0.25 x 2.5 inches. It is very suitable for Minibow Aquarium Filters Size 1 / 2.5 / 5 gallon and QuietFlow E Internal 10 on the market. With this aquarium filter cartridge, you can keep your aquatic organisms healthy every moment. It contains 12 pack aquarium filter cottons, which you can change every 2-4 weeks. Excellent Filtration Performance: The filter cotton is made of cotton and activated carbon, which can filter and absorb 99% of the bacterial impurities harmful to fish, so as to keep the water source clean and the healthy growth of fish. Quick Installation: Turn off the power in less than 5 minutes, thereby improving time efficiency. Resuming daily activities quickly and filtering in the process that makes a big difference. Just remove the old and dirty filter and replace it. Protect the health and safety of your fish all the time.