The 7cm diameter ball-airstone, perfect for adding oxygen to your aquarium. It works by releasing tiny bubbles into the water, increasing oxygen levels and providing a tranquil, bubbling water feature. It is made of a durable, non-toxic material and is designed to fit standard aquarium tubes, allowing you to customize your tank's aeration. The ball-airstone is an easy, affordable way to oxygenate your tank and keep your fish healthy and happy.