Uxcell Air Pump Bubble Diffuser Aquarium Airstone Disk, Gray/White Product Name : Aquarium Air Stone; Suitable for : Aquarium Design : Round; Material : Mineral, Plastic Diameter : Outer Diameter: 9cm/3.5", Inside Diameter:7cm/2.8"; Total Size : 9 x 1.2cm /3.5" x 0.5" (D*T) Color : Gray, White; Net Weight : 69g Package : 1 x Air Stone