The machine-drilled holes of Bubble Pipe create tiny uniform bubbles, thousands every minute. A wall of air produced by these tiny bubbles beautifully and interestingly decorates your aquarium by continuously changing its shape. Unlike conventional materials (air stone etc.), Bubble Pipe does not easily get clogged. Even if it should get clogged, Bubble Pipe can be easily cleaned with pipe brush. Made of hard plastic, Bubble Pipe may be placed anywhere in your aquarium. Can be assembled into one 15` bubble pipe or two 7-1/2` bubble pipes. Info from the Aquarium