The Schneider Electric (Erie) VT2213G13B020 is a multifunctional 1/2-inch snap switch designed to efficiently manage a wide range of HVAC equipment. It controls the flow of electricity by acting as a gatekeeper and operating as a typically closed switch. When it is in the "on" position, the circuit is completed and linked items can now receive electricity. https://www.partshnc.com/vt2213g13b020-schneider-electric-erie-12-sw-35cv-nc-120v-onoff