The Ista Metal Air Valves allow you to control up to 2 or 4 different airlines from your air pump. Quickly and easily attach this handy device to the frame of your aquarium and streamline your air hose setup. With a control knob available for each outlet, you can adjust the pressure on each air tube individually. Customize the use of your air stones, bubbles, air-driven decorations, or any other air pump powered device. 1.5" x 1.25" x 3"