This is not easy to use. It does beep at areas and has found bad spots but also beeps where there are none. Does not work well with chasing or motion lights or on those holiday display items with more then one circut. It does work on single light stands and the older corded plugs to fix circuts or current running through but does not allow for the double or should I say tripple string strand sockets. (it's not large enough) The bulb puller is hard to use and has to be put in place like an old fashioned can opener and it felt like it would easily break the bulb. In my opinion it was easier to pull every bulb and test it with the old 9volt bulb tester I have. Did not accurately test bulbs either. I tossed several then my hubby tested same bulbs with my old one and they were good bulbs. It did work on testing fuses but hard to get into area for test. It's ok but should be a $5 cheep unit not a $20 unit.