A rocker switch is an on/off switch that rocks (rather than trips) when pressed, which means one side of the switch is raised while the other side is depressed. A rocker switch may have a circle (for "on") on one end and a horizontal dash or line (for "off") on the other to let the user known if the device is on or off. Rocker switches are used in surge protectors, display monitors, computer power supplies etc.