Texas Pneumatic Tools push pins are used with proportional throttle valves to fill the performance gap between conventional solenoid operated directional valves and servo valves / feedback-type proportional valves. They combine direction and flow control capabilities in one package. These push pins are used to turn the spool of throttle valves when a current is passed through solenoid coils. The push pins turn the spool until the solenoid force is balanced by the return spring force.