Plunger Switch Momentary Square Normally Off Single Pole Single Throw

A plunger switch has an actuator that makes or breaks the circuit contact when its button is depressed. A momentary switch, sometimes called a spring return switch, automatically returns to the rest position. A normally OFF switch (also called a normally open circuit), remains in the OFF rest position until pressure is applied to the actuator. Single pole, single throw (SPST) is a two terminal switch that opens or closes one circuit.