Medium Bubbles: The air stone balls produce abundant dense bubbles. A great way to increase oxygen solubility in your aquarium and enliven the aquatic lives. Model: ASB050; Jetting volume: 5 L/min; Recommended air pump power: > 4 W; Standard ID airline tubing: 0.5cm or 0.9cm. Well-built and efficient for long-time service. Reliable Material: Made of mineral material and sintered at a high temperature. Great for aeration in aquariums, DWC systems or ponds. Keep fish or roots growing healthily. Stable in Water: Each ball measures 5cm in diameter and weighs 106g Well weighted to sink to the bottom and lie stably in your tank for steady bubbles. Easy to Use: Soak the stone completely in water for 1 hour before use. Clean it regularly with a brush as it gets clogged after weeks or months of usage.