Features: Improve your aquarium's oxygen level and improve water quality with our efficient Oxygen Bubble Stone, promote healthy growth of your fish. The stone is sturdy and durable. It can be used for long time and get better dissolved oxygen effect. When bubble burst into the water, the sound is super quiet. Great accessories for fish enthusiasts, aquarium operators, and home aquarium users want reliable aeration solution. Suitable for home aquariums, office fish tanks, and small decorative aquariums, ensuring a better environment. Need to connect air pumps for use. Specifications: Component: Plastic, Sandrock Color: 2 Option Type: Square/Round Size of Square: Approx.6x5cm/2.36x1.97inch Size of Round: Approx.5.5x5cm/2.17x1.97inch Quantity: 1 Pc Package Includes: 1 pc Air Stone note: 1.Please allow 1-2cm errors due to manual measurement, note that you donot mind before order. 2.Due to the differences between different monitors, the picture may not reflect the actual color.