Features: brand new and high quality brand new and high-quality Made of ceramics and sand, after high temperature sintering, great air diffusion, good filterability, corrosion resistant. Increase oxygen levels, lower CO2, creates water current. It is an important instrument to successfully keep aquatic fish for breathing process. Durable, can be reused and washed repeatedly. Creates tiny bubble in fish for tank while attached to an air pumps (air pumps and air tube is not included). - Specifications: Material: Ceramic, Sand Color: As Pictures Show Size (Approx.): 5.5x5.5cm/2.16x2.16in Weight (Approx.): 350g Package Includes: 1 Piece Air Stone Disc 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!