High porosity airstoner produces an even flow of fine pearlescent air bubblesr minimal back pressure maximises the full capacity and liftetime of your air pumpr manufactured to high quality specifications for longer lifer tetratec airstones are designed to be run with any aquarium air pump such as the tetratecaps range and standard aquarium airline hosefor maximium aeration the airstone should be placed as deep as possible within the aquariumr dimensions 27mm x 40mm long