5PCS/10PCS 2cm/3cm/4cm/5cm Fish Tank Aquarium Air Stone Oxygen Aerator Increasing Air Bubble Pond Pump Hydroponic Oxygen Supply Great Fish Tank Aquarium Air Stone Oxygen Aerator Increasing Air Bubble Pond Pump Hydroponic Oxygen Supply Stone 2cm/3cm/4cm/5cm Features: Ozone aerated stone, bubble stone, using super hard gold steel sand, after high temperature sintering, good gas diffusion, good filterability, ozone resistance, corrosion. Increase oxygen levels, lower CO2 and raise PH, creates water currents. It is an important instrument to successfully keep aquatic fish for respiration process. Durable, can be reused and washed repeatedly. Creates bubbles in fish tank while attached to an air pump(air pump and air tube is not included). Specifications: Color: As picture Material:hard gold steel sand Diameter 2cm: total height 33mm, diameter about 20mm (not including the nozzle size) nozzle diameter: 4mm, 0.01KG Diameter 2.5cm: total height 38mm, diameter about 25mm (not including valve size) nozzle diameter: 4mm, 0.015KG Diameter 3cm: total height 44mm, diameter about 30mm (not including the nozzle size) nozzle diameter: 4mm, 0.02KG Diameter 4cm: total height 66mm, diameter about 40mm (not including the nozzle size) nozzle diameter: 4-6mm, 0.06KG Diameter 5cm: total height 76mm, diameter about 50mm (not including the nozzle size) nozzle diameter: 4-6mm, 0.1KG Note: Soak in water for 15 minutes before use. For long-term use, if there is dirt blockage, and the bubbles is reduced, please take it out of the fish tank and wash it again and again. The air stone can be used repeatedly. Please allow 1cm differs due to manual measurement. Due to the different display and different light, the picture maybe a little different with the actual color of the item. Thanks for your understanding. Included: 5pcs/10pcs aquarium fish tank air stone(optional)