Tecno elettrica ravasi (t.e.r.), prsl1857bi transparent 1/0/2 spring returned selector switch, use w/ mike & victor pendants this selector switch is compatible with mike and victor control stations. It is designed to let the user control more than one motor function with the same control station. The most common configuration utilizes two prsl 1800 pi switches and an led element. The selector pointer is made of a translucent plastic for backlighting when an led contact is installed in conjunction.