The Triplett ET102 is a useful and necessary tool for residential and commercial electricians, home inspectors, and DIYs, you can detect faulty wiring in 3-wire receptacles. Lights display 5 wiring faults: Open Ground, Open Neutral, Hot/Ground Reverse, Open Hot, Hot/Neutral Reverse with an easy to read fault label on both sides for receptacles with ground up or ground down installation. Unique Loop Design allows for easier pulling removal when testing is complete. cULus Listed.