Aquarium Mini Cylinder Mineral Bubble Air Stone Pond Fish Tank Pump Aerator Aeration Hydroponic Oxygen Airstone Accessories for Air pump 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: Grey Material:hard gold steel sand Item Size: Dia. 2cm Height: 7.5cm Suitable for air tube: Inner dia. 4mm.; Outer dia. 6mm Package include: 1*air bubble stone /3pcs air bubble stone/1pcs air bubble stone+2m air tube. Note: -Soak in water for 15 minutes before use. -For long-term use, if there isdirt blockage, and the bubbles is reduced, please take itout of the fish tank and wash itagain 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 withthe actual color of the item. Thanks for your understanding. 1pcs aquarium fish tank air stone _x000D_