Free Position - Position of the actuator, without any influence from an external force

Operating Position - Position of the actuator when contact changeover takes place

Total Travel Position - Position of the actuator at the end of the allowed travel

Actuating Force - The force required to move the actuator from the free position to the operating position

Force Differential - Difference between actuating force and release force

Pre-travel - Movement of the switch actuator between free and operating position

Over-travel - Movement of the switch actuator beyond the operating position

Total Travel - The sum of pre-travel and over-travel

Insulation Resistance - resistance as measured between the normally closed terminals, or between all terminals connected together and a metal plate to which the switch is mounted. In dry conditions the value would be expected to be greater than 5MΩ.

Switch Resistance - a total resistance offered by a switch in a circuit, as measured from terminal through mating contacts, to terminal.

Transit Time - the time taken by the moving contact in a snap-action mechanism to move from one stable position to another.