Air Stone Ball: Size: 2.7 inches in diameter; Weight: 11.3 oz. The air stone balls are well-constructed for continual bubbling. Ideal for fish tanks, DWC systems or small ponds. Medium Bubbles: The air stone balls produce a good amount of dense bubbles. A great way to increase oxygen solubility in your aquariums and enliven the aquatic lives. Steady Output: Jetting volume: 15 L/min; Recommended air pump power: > 7 W; Required airline tubing: 3/16" or 3/8" ID tubing. Efficient bubbler for constant air diffusion. Reliable Material: Made of mineral material and sintered at a high temperature, it causes no effect to the health of your aquatics. Help keep your fish or roots growing healthily. Easy to Use: Soak the airstone completely in water for 1 hour before use. Clean it regularly with a brush as it gets clogged after weeks or months of usage. Sintered with high temperature, it is well built to keep stable in water and withstand long-time use. Perfect for oxygenation in both fresh and salty water environment like fish tanks, koi ponds, DWC reservoirs, aquariums, etc.