new, high quality. Use with a filter outside the fish tank.Compact and simple installation.Acid and impact resistance. Ensure that CO2 is dissolved into the water in large quantities. Dissolves carbon dioxide gas into the water, providing the CO2 required for the growth of aquatic plants. High efficiency 100% completely dissolved, more suitable for aquatic plants to absorb and utilize. Colour:As Shown Material:plastic Capacity: 2500ML Applicable fish tank: ≤ 600L Due to different batches, there may be differences in product appearance and printed text, which will not affect use Package Contents: 1 * CO2 diffusion drum 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.