The air stone is used to produce bubbles, reduce the noise level inside the aquarium, and supply the oxygen. The volume and pressure output of your air pump will determine how large an area of the stone will release bubbles.

Mineral sand air stone is made of special washed sand. It is fine-meshed and better for effluent air.

Carborundum air stones, which is shaped with 1300 'C, is made of carborundum. It is strong with nice outlook, and good for diffusing air.