DescriptionThis ball shape air bubble stone is made of fine sand material for durable and long-lasting use. Designed to add oxygen and circulate nutrition to your hydroponic growing system or aquarium. Suitable for hydroponic systems, ponds, aquariums, fish tanks and other systems.Feature- Color: As Shown. - Material: Sandstone. - Size: 2.00X2.00X3.50cm/0.79X0.79X1.38inch. - Adopted of premium material, it is practical and durable with long service life. - Increases air flow circulation to oxygenate water that isbeneficial to aquatic animals.- Lightweight and compact, easy to operate. Unique appearance, simple and stylish. - A great way to add oxygen to your aquarium, fish tank, hydroponic and circulation system. - The bubbles are uniform, small and dense, with good oxygenation effect.