The AquaTop BREZA Sand Airstones are uniquely shaped and boast an incredibly porous surface, which allows for consistent even air distribution. This even air flow creates a beautifully consistent column of bubbles. AquaTop BREZA Sand Airstones provide the oxygen your aquarium fish and plants need for a healthy life. Made from pressed sand, the BREZA airstones allow for uniquely even air distribution in the tank, with a notched shape to increase bubble-producing surface area for maximum aeration.