Features: A great way to properly aerate a home aquarium, help to keep fish healthy and adds to the beauty of the aquarium. Increase oxygen levels, lower CO2 and raise pH. It is an important instrument to successfully keep aquatic fish for respiration process. Durable, washable and sintered by high temperature, different from other air stones. Creates bubbles in fish for tank while attached to an air pump. Creates water currents and dazzling underwater scenes. Easy and convenient to use. Specifications: Suitable for inner diameter 4mm soft tube. Material: Gravels, Plastic Diameter: app.1.5cm/0.59in Height: app.4cm/1.57in Package Includes: 1 x Aquarium Air Stone (without retail package) note: 1.Please allow 1-3cm 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!