Features: Improve your aquarium's bubble and improve water quality with our efficient CO2 Diffuser, promote healthy growth of your fish. It can be used for long time and get better dissolved bubble effect. When bubble burst into the water, the sound is super quiet. Great accessories for fish enthusiasts, aquarium operators, and home aquarium users want aeration solution. Suitable for home aquariums, office fish tanks, and small decorative aquariums, ensuring a better environment. Need to attach air pumps for use. Specifications: Component: 304 Stainless Steel Type: 6 Option Size 1: Approx.25cm/9.84inch Size 2: Approx.30cm/11.81inch Size 3: Approx.35cm/13.77inch Size 4: Approx.40cm/15.74inch Size 5: Approx.63mm/2.48inch Size 6: Approx.25x30mm/0.98x1.18inch Package Includes: 1 pc Aquarium CO2 Diffuser note: 1.Please allow 1-2cm errors due to manual measurement, note that you donot mind before order. 2.Due to the differences between different monitors, the picture may not reflect the actual color.