Hang on 4 Way Air Pump Manifold Valve Taps REMOVABLE for 4/6mm tubing line tube by Aquarium Equip The Hang on 4way air control valve -Allows the user to adjust the amount of air flow entering the aquarium. It allow the are flow of the air pump from one into multi ways! The outlet air standard size for air line tubing aquarium (4/6 mm). Will not leak up to 8.5 p.s.i. Hanger fits all standard aquariums Suitable for fresh or saltwater.