The microporous design and airtight construction produce fine, evenly distributed bubbles to maximize oxygen replacement and reduce CO2 levels. Quality materials. The air bubble stone is made of high-quality sand and plastic. Strong, durable, non-toxic, and safe for fish. With a long service life. Easy to use. The inlet is compatible with standard airline tubing. Connect to the air pump and put it in the water, helping the air pump pump oxygen into the water. Widely used. The device is easily installed in hydroponic systems, ponds, aquariums, tropical fish tanks and more. Connection diameter: 4 mm. Stone length: 11.6 cm. Total dimensions: approximately 11.6 x 1.9 x 1.2 cm. Package contents: 10 x Air Bubble Bar Diffuser