UNI-T AC Circuit Breaker Finder with Integrated GFCI Outlet Tester AC 90-120V USA Plug + Adjustable Sensitivity Beeper Indicattion+ Flashing LED Light

You simply plug the tone generator unit (which also works as an outlet tester) into an outlet, and tone is automatically sent to the circuit box. If the circuit is off, however, the tone sender unit is not powered, and no tone is generated.

This works well on standard breakers. It works okay on double circuit breakers, as it can be tough to determine which portion of the double breaker is actually the right one since the sensor head is large enough to cover both. The key in general is to adjust the sensitivity high enough to see the flow of electricity, but as low as possible, so that you can isolate the one circuit breaker that is actually active. The fact that the transmitter unit also functions as a circuit tester, and a GFCI tester, is a nice added feature. One 9v battery is required and is included. It is inside the receiver and must have the plastic wrapper removed and then be connected. The included zippered storage case is nice. The English translation of the one page Operations Manual is usable.

Love this product

This is a great tool to track down circuits in your home or office. easy to use, and works well. does a good job of helping you figure out what is what in the breaker box.

This works pretty well for identifying breakers on a circuit. In my case, I had to put the sensitivity at the lowest level and as others have reported, you have to hold the wand in a verical fashion. Having the GFCI / circuit tester is icing on the cake. My second Uni-T product, both well made. I only wish this unit used double or triple-A batteries instead of a 9v battery. Still a 5-Star item.