At its simplest, a switch makes or breaks an electrical circuit. The basic components of a pushbutton switch include: the actuator, which activates the switch; the bushing and bezel, which allow the switch to be mounted on a panel; the contacts, which create the passageway for the electrical current; the sealing membrane, to protect the switch; the case, which holds the contacts and provides insulation; and the terminals, which connect the switch to the customer environment, be it power source or PCB. If the switch is illuminated, it will also include an LED. In pushbutton switches, the contacts remain in either an open or closed state until activation. Activation causes a state change which can be either momentary, in which the state is changed only while the actuator is being depressed, or latching, in which the state changes until a second, subsequent activation.