Every VULCANO airstone is a unique, selected piece of genuine volcanic rock.
By means of the internal hollowing-out of the stone, the air seeks the path of least resistance, giving a different air output at different points.

Large air bubbles can thus be expelled even without the use of a powerful airpump.
The underside is flat for easier installation in the tank.

Attention:
Every stone is individually finished and tested.
Evey stone has different sizes and lookings