Why just use your aquarium gravel as decoration? With the addition of an Undergravel filter you can turn your gravel bed into a biological filter that is easy to maintain and simple to use. The Lee's original undergravel filter is designed with adjustable 1" uplift tubes for better water circulation. Easy to install. Includes: plates, airline tubing, uplift tubes, air diffusers and carbon cartridges. Can be used with a powerhead.