Use the Power Steering Evac Plug with Mityvac hand vacuum pump to evacuate trapped air from power steering systems. It has a universal design that adapts to most power steering reservoirs. The Power Steering Evac Plug is easy to connect and simple to use. Featuring a universal cone-shaped rubber body, the MVA660 adapts to the varying diameters of many automotive power steering reservoirs to form an airtight seal when vacuum is applied. Once the adapter is installed and a Mityvac hand vacuum pump is connected, the air bubbles can be loosened by simply working the steering.