Product: Hobby Vulcano - air diffuser
Every Vulcano airstone is a unique, selected piece of genuine volcanic rock. By means of the internal hollwing-out of the stone, the air seeks the path of least resisance, giving a different air output at different points. Large air bubbles can thus be expelled even without the use of a powerful pump. Every stone is individually finished and tested, and then ftattened off on the undersite for easy and stable positioning.