Non-toxic mineral material. The air stones are made of high-quality, non-toxic minerals, the stones are solid and durable. Size of the aquarium air stone 15 x 25 mm / 0.59 * 0.98 inches (D x H). Recommended power for air pump: approximately 2 W-4 W. Oxygen supply. Connect it to the air pump and place it in the water so that the air pump can pump oxygen into the water. Perfect for adding oxygen to ponds, hydroponic systems and continuous flow systems and reducing CO2 levels. Widely used. These air stones can be used in aquariums, ponds, freshwater, saltwater aquariums, hydroponic aquariums or in aquaculture. Small, dense bubbles produced by air stones can not only provide oxygen to fish, but also create beautiful and magical underwater bubble scenes. Easy to clean: If the aquarium air bubbles are covered or blocked by algae and impurities, you can easily clean it with a very practical brush. You can use it for a long time. We suggest cleaning it once a month to get an excellent effect.