The inlet/outlet ports of a pneumatic actuator are directly connected to Namur solenoid valves. The purpose of a Namur solenoid valve is to regulate the flow of media: the valve is controlled by an electric solenoid, which opens or shuts the valve by controlling the quantity of air that passes via a pilot to the pneumatic actuator.
It comes in various port sizes from 1/8″ to 1/2″. And various voltages available are 230V AC, 24V DC, 110V AC, 24VDC, 12V DC.