This product is well-made of and materials, durable and practical. Effectively remove some bad substances in water. Use these fish tank filter materials to decompose impurities, stabilize PH value, purify your water naturally, and cultivate beneficial organisms. Features - Color: Assorted Color. - Material: activated carbon. - Size: Approx. 3.00X3.00X3.00cm/1.18X1.18X1.18inch. - Packing Size: About 20x10x5cm/7.87x3.94x1.97inch. - Note: A total of two catties, 1 catty activated carbon and 1 catty 13-in-1 filter material pack. - Durable, high porosity material can effectively remove some bad substances. - for personal home fish tank or aquarium large fish tank use. - Can be perfectly integrated with other decorations in the fish tank. - This product is made of safe and material, durable and use. - They can help form a good ecological cycle, very safe and practical. Package list: 1 x set of fish tank filter materials (2 catties)