Sometimes receptacles, often called outlets, have problems and don't work properly. It may be that the wires are connected to the wrong terminals, there is a bad connection, or that the outlet is damaged in some way. More times than not, inspecting the receptacle with your eys may not tell the story. It may look as if everything is normal, but with a receptacle analyzer, you'll be able to know the true story about your outlets. With three LED lights, it can tell you things like polarity, open neutral, or open hot wire connections. It will also tell you if there is no ground connection on your outlet. So if you want to investigate your receptacles for being defective or miswired, the receptacle analyzer is for your!