What is a pneumatic solenoid operated 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.
