Solenoid On/Off Valve Poppet-Type Solenoid Valves Normally Closed Poppet, 2-Way, Normally-Closed Normally Open Poppet, 2-Way, Normally-Open Spool-Type Solenoid Valves Spool, 2-Way, 2-Position Spool, 3-Way, 2-Position Spool, 4-Way, 2-Position