spool valve
A spool valve is a multidirectional hydraulic or pneumatic valve usually operated by a joystick. It has several hoses attached to it leading to different pneumatic rams. When the joystick is pushed in one direction, it causes the valve to shut off one of the pneumatic hoses leading to the ram and open the other. Which way the joystick is pushed moves the piston in the ram in or out. Since you specified a solenoid operated valve it is operated not by a joystick that is directly connected to the valve but rather an electric joystick like the you would use in a video game and an electrical signal is sent to activate a solenoid that does the same thing but can be much farther away from the operator.
Solenoid Actuated Pneumatic Spool ValveA solenoid actuated pneumatic spool valve is a spool valve actuated by an electric solenoid. They are often used in industrial automation and are usually controlled by a PC or a PLC (Programmable Logic Controller) rather than a manual switch. To reduce the size and power consumption of the solenoid, often the solenoid does not directly actuate the spool. Instead, the solenoid actuates a small internal valve which directs upstream air pressure to move the spool. This is called an air piloted solenoid actuated pneumatic spool valve. The air pilot mechanism typically requires about 40 PSI to operate reliably. If the air pressure upstream of the valve is going to be less than 40 PSI, the valve must be externally piloted, meaning that the pilot is connected to a separate air source which is above 40 PSI.