Compact yet robust: Each air stone measures 1.5 cm wide and 2.5 cm high and weighs 8.5 grams. Despite its small size, it has a robust construction designed for continuous bubbling. It is ideal for use in small aquariums or fish tanks. Medium bubbles: This cylindrical air stone generates a large volume of dense bubbles. It is an excellent way to increase oxygen levels in your aquarium and enrich the aquatic environment. Reliable materials: Made from mineral materials and sintered at high temperature, these aquarium air stones pose no health risks to your aquatic inhabitants. They promote the healthy growth of your fish. Easy to use: Before use, completely submerge the air stone in water for one hour. Clean it regularly with a brush, as blockages can occur after several weeks or months of use. Note: Compatible with flexible hoses with an inner diameter of 4 mm. Before use, soak the air stone in water for 15 minutes. If the air stone does not produce bubbles evenly across its surface, use a more powerful air pump. This product will not function correctly if installed directly on a submersible pump.