Air Manifolds allow the adjustment of airflow to four or more air stones or air diffusers to insure that equal airflow is provided to each air diffuser or air stone. The manifold has individual barbed valves which control the outlet of air to your air stones or diffusers. They also allow excess air pressure from the pump to escape to decrease pressure on the diaphragm of your pump. Compatible with Air Force Pro? 40, 60, & 80. Use with 3/16 in ID air line product #708215 or EcoPlus? Pro Linear Air Pumps 20, 40, 60, & 100.