Medium bubbles: Air stone balls produce dense and abundant bubbles. A great way to increase oxygen solubility in your aquarium and enliven aquatic life. Jet volume: 5 L or min Recommended air pump power: >4W Standard ID Air Hose: 0.5cm or 0.9cm. Well constructed and efficient for long time service. Reliable material: made of mineral material and sintered at high temperature. Ideal for aeration in aquariums, DWC systems or ponds. Keep fish or roots healthy Stable in water: Each ball measures 5cm in diameter and weighs 106g. Well weighted to sink to the bottom and sit stably in your tank for stable bubbles. Easy to use: Fully soak the stone in water for 1 hour before use. Clean it regularly with a brush as it becomes clogged after weeks or months of use. Quantity delivered: 2 pieces Product color: blue Product specifications: as shown in the picture. Welcome to meet