This neon light mounts on the bottom side the HE440 control panel. The light is on when ever the heating element is hot. Mounts in a ½" dia hole. Electrical: 125 vac. Two 6" leads with ¼" quick connect terminals. To test this neon light, connect its leads to 120 vac. For HE440 wiring info, see the schematic on page 11 of the HE440 Product Data manual. A similar neon light is the F876-0105.