Features: The aquarium filter water cube is made of activated carbon, dense grid hole structure. It can absorb 99% of harmful substances in the aquarium, as well as odor. It can effectively reduce the nitrate in the aquarium and adjust the PH value. Change or clean every 3 or 6 months, save to your energy and time. Great filtration material. Notice: Actual color may be slightly different from the image due to different monitor and light effect Please allow 1-3cm deviation due to manual measurement This product is made of molds and is fragile due to the porous cellular design. Therefore, when receiving the goods, there may be slight defects or separation on the edge, which is a normal phenomenon and does not affect the use function. Don't bid if you mind. Specification: Size: 10cmx10cmx5cm Material: Active Carbon Structure: Dense Grid Hole Caution: 1. Rinse clean and then use; 2. Please don't put the black mesh downwards, otherwise the mesh will be clogged up; 3. rince or replace every 3 or 6 months, or when you find the filtration effect is lower. includes: 1x Aquarium Filter Water Cube