Security or emergency lighting fixtures that are typically mounted above drives and entryways, often fitted with a proximity sensor along with a daylight sensor.
The raccoon set off the booger light again, but he doesn't seem to mind. The bugeye in the hallway doesn't work.
This device is useful for quickly determining if a receptacle has power and if there is anything obviously wrong with the wiring. Enhanced models perform GFCI testing but this tester is essentially idiot-proof through the use of three lights and a sticker explaining the meaning of these lights.