Solidified Air Bubbles where greatly depended upon by the Matoran in Mahri Nui. They could be extracted from an underwater plant called Airweed which the Hydruka could obtain for the Matoran. While outside Mahri Nui, Air Bubbles could be used to hold Matoran in them and breath underwater while outside the city.
The Matoran of Mahri Nui later found a way to use the air bubbles against aquatic Rahi. After studing the natural way the Hydruka had defended themselves the Air Launcher was created to fire them. Water-breathing Rahi would become poisoned by the effect of the gas when strucked.