Perfect Replacement Cartridges: ONLY Fit for Quiet Flow LED Filter Size 10, QuietFlow Power Filter Size 10 and QuietFlow E Internal Power Filter Size 20. Fine Carbon Filtration: Contain 3 times more activated carbon than other cartridges. Fully absorb and filter impurities or damaging substances to deodorize the water and reduce unhealthy gases. Further Cleaning: The outer layer is made of with high-density fiber. The multi-layer cotton traps debris or waste without sucking up your fish, keeping water and . Reliable Material: It is well-designed with little leakage of carbon powders and 't contaminate the water. And the evenly distributed cotton 't block the normal water flow. Easy to Use: Before use, rinse it with cool water to remove the outside dust, then put it completely into the filter chamber. Replace it every 2 to 4 weeks to maintain a healthy water environment. Colour:As Shown Material:activated carbon Size:S: 9.1 x 7.1cm Package Contents: 6 x filter elements Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.