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/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 Note: 1. Please allow 1-3 mm error due to manual measurement and 1-3g weight error make sure you don't mind before ordering. 2. Due to the lighting of the photos and the difference of monitors, the pictures may not reflect the actual color of the real item. Please make sure you don't mind before ordering, thank you! About Shipping: 1.please pay attention to your delivery address such as: name, street, house number, doorbell/email without name, etc. is correct, or the order will not be delivered correctly. 2.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. 3.During the shopping process, if you have any questions, please feel free to consult us, we will reply you within 24 hours Hope you have a pleasant shopping experience!