Selector switches can be rotated right, left, or centered to open or close the electrical contacts. The function of a rotary selector switch is to control a device and switch between a minimum of two or more circuits. A perfect use for a selector switch is to control the output of a device. For example, on an audio device, a selector switch can be used to connect an audio output to multiple sets of speakers. Selector switches supply as a complete unit, usually listed as a terminal block, which means that the selector switch is a complete block (consisting of the selector switch actuator, contact block and fixing collar), which makes installation simple easy.