Features:

Widely applicable: Suitable for hydroponic systems, circulation systems, aquarium fish tanks, helping extend the life of your nutrient solution, keep fish/ roots healthy and promote plant growth

Material: Durable and sturdy material, safe to your fish

Dimension: 4.1" D x 0.8" H; Fits standard airline tubing aquarium and CO2 tubing with inner diameter of 3/16"

Stable in water: The 3 suction cups can be attached to the tank, keeping it stable in water when bubbling

Note:

You have to soak it in water for about 60 minutes before connecting to an air pump to run it

Includes:

1 piece of air stone with 3 suction cups