Features: brand new and high quality Ultra-high dissolved oxygen: This upgraded air stone releases the bubbles more smaller, denser, uniform, which makes double oxygen dissolving rate in water. Produces small & dense bubbles quietly: Push 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. Size: The diameter of air diffuser area is 2 inch, not including the plastic border, suitable for freshwater and saltwater. Package Includes: 1 Aquarium air stone disc, 1 suction cup, and 1 regulating for valve. Safety Material: Made of mineral stone, safe for fish and water. Specifications: Material: Mineral Stone Color: White/Blue Size (Approx.): Inner Diameter 50mm/1.97in, Outer Diameter 74mm/2.91in, Height 24mm/0.94in Weight (Approx.): 200g Package Includes: 1 Piece Air Stone Disc (White/Blue) 1 Piece Suction Cup 1 Piece Regulating for Valve note: 1.Please allow 0-1cm error due to manual measurement. pls make sure you do not mind before you bid. 2.Due to the difference between different monitors, the picture may not reflect the actual color of the item. Thank you!