Perfect Replacement Cartridges: ONLY fit for Quiet Flow LED PRO Size 10 Power Filter, QuietFlow Size 10 Power Filter and QuietFlow E Size 20 Internal Power Filter. Fine Carbon Filtration: Contains 3 times more activated carbon than other cartridges. Fully absorbs and filters impurities or harmful substances to deodorize the aquarium and reduce unhealthy gases. Extra Cleaning: The outer layer is made of soft cotton with high-density fibers. The multi-layer cotton traps debris or waste without your fish, keeping the aquarium crystal clear and fresh. Reliable Material: It is well-designed with little leakage of powders and will not contaminate the aquarium. And the evenly distributed cotton will not block the normal flow of water. Easy to use: To use, rinse it in cold water to remove external dust, and then place it completely in the filter chamber. Replace it every 2 to 4 weeks to maintain a healthy aquatic environment. Color: as shown Material: activated carbon Size: M: 10.5 x 11.5 cm