Tecno elettrica ravasi (t.e.r.), prsl1855bi transparent 0/1 spring returned selector switch, use w/ mike & victor pendants this selector switch is compatible with mike and victor control stations. This selector is commonly used for off, on applications. For off, on applications only one prsl 1800 pi n.o. Contact is required. The selector pointer is made of a translucent plastic for backlighting when an led contact is installed in conjunction.