Features: Made of high-grade material, which is non-toxic, safe, energy-saving and eco-friendly. Provides precise and clear carbon dioxide bubbles. Simple design, the best safety performance. Easy and convenient to use and install. Also come out with excellent dissolved rate and produces excellent effect for the aquarium. Specifications: Condition: 100% Brand New Diffuser Material: Stainless Steel Atomizing Nozzle: Approx. 2cm / 0.8", 3.05cm / 1.2" (optional) CO2 Diffuser Length: Approx. 20cm / 7.9", 25cm / 9.8", 35cm / 13.8", 40cm / 15.7" (optional) Package Weight: Approx. 6g~205g Package Include: 1 x CO2 Diffuser Or 1 x Atomizing Nozzle . Note: It is normal that large bubbles will appear on the thinner sheet at the beginning of use. After 24 hours of continuous use, the large bubbles will gradually decrease, and the large bubbles will disappear within 3 days at most.