Commercial Electric OTG-102R is GFCI Receptacle Tester. It is designed to detect the most common wiring problems in standard receptacles. The tester can detect conditions such as wiring correct, open ground, reverse polarity, open hot, open neutral and hot/ground reversed. GFCI outlet tester was designed to detect the most common wiring problems in standard or GFCI receptacles Conditions indicated: wiring correct, open ground, reverse polarity, open hot, open neutral, hot/ground reversed Multi-function tester with very low price Easy to operate with light indication Only used once, comes with original packaging