These PA Air Curtains are special inlets made from a special porous rubber available in 5 different sizes. When connected to a air pump the air way exit the Air Curtain through the pores within the rubber. Likewise, submerged within water or nutrient solution, this produces small bubbles which which oxygenises the solution. Furthermore, also decreases the chances of root diseases. Therefore adding an airstone or air curtain to your reservoir increases the speed in which your develops. In turn, creating far larger and healthier plants.