... offer available) Single-control solenoid valve: Valve opens or closes when power on , vice versa(explosion-proof offer available) Double-control solenoid valve: Valve opens when one ... contracts1). Pneumatic Actuators , (1) Double-Acting ,(2) Single-Acting ,(3) Model2). Solenoid Valve, (1) Single-Control Solenoid Valve ,(2) Double-Control Solenoid Valve ,(3) Voltage ,(4) Explosion ...