this upgraded air stone releases the bubbles more smaller, denser, uniform, which makes double oxygen dissolving rate in waterpush out amounts of smaller and denser smooth bubbles than others, when the bubbles burst into the water, the sound is quieter.It can creat the atomization effect and bubble beams will make your aquarium like a fairyland.easily sits on the bottom without suction cup. The diameter of air diffuser area is 2 inch, not including the plastic border. Suitable for freshwater and saltwaterSuper sturdy durable, service life can be 2 to 3 years.Weighs enough to sink in the bottom, no need suction cups.Dissolve more oxygen to the water.Nice high output of amounts of bubbles.Strong filtration, for fresh and salt water.White color and disc shape, good decor for your aquarium.Easy to clean.colour:WhiteMaterial:sand stonesize:7cmPackage Contents:2 * bubble stone2 * air valve2 * check valve4 * suction cupsOnly the above package content, other products are not included.Note: Light shooting and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.