Medium Bubbles: The air stone produces abundant dense bubbles to aerate your water reservoirs. A great way to increase oxygen solubility in fish tanks, aquariums or ponds. Model: ASD-200; Jetting volume: 28 L/min; Recommended air pump power: > 15 W; Inner diameter of tubing: 3/8". NOT suitable for standard 3/16" airline tubing. Reliable Material: Made of mineral material and sintered at a high temperature. Great for aeration in a DWC reservoir. Help keep fish or roots growing healthily. No More Floating: Measures 8.4" D x 1" H and weighs 2.9 lbs, which helps it sink to the bottom easily. And the 3 suction cups tightly suck the tank to make it sit stably in water. Easy to Use: Soak the stone completely in water for 6 hours before use. Clean it regularly with a brush as it gets clogged after weeks or months of usage. Medium Bubbles: The air stone produces abundant dense bubbles to aerate your water reservoirs. A great way to increase oxygen solubility in fish tanks, aquariums or ponds.