GUOXING Fine Bubbles: The air stone disc produces lots of dense medium bubbles. A great way to oxygenate your hydroponic growing systems, ponds, aquariums and enliven the aquatic life. jetting volume: 12 L / min; recommended air pump power: > 4 W; standard ID airline tubing: 4 mm. Durable Material: Made of mineral material and sintered at a high temperature. Great for aeration in a DWC reservoir. Help keep fish / roots growing healthy. wer: 4W-8W. Stable in Water: weighs 198g. 3 strong suction cups easily fix it in the smooth aquarium, allowing it to lie steadily in the tank.Stable in Water. Easy to Use: Soak the stone completely in water for 1 hour before use. Clean it regularly with a brush as they get cl ogged after weeks or months of usage. the smooth aquarium. Delivery Quantity: 1pcs Product color: black Product size: 10.8*1.9cm About Shipping: All items will be shipped within 3 business days after the payment is received. Most times you will receive them within 8-12 days then. The specific delivery time is depend on circumstances.Any questions, please feel free to contact us During the shopping process, if you have any questions, please feel free to consult us, we will reply you within 24 hours, wish you a happy shopping Thanks for your cooperation and we'll make you feel satisfied.