I first bought this unit to try and find the wiring for 5 outlets that were not powered and didn't show up in the electrical box. Triplet 3375 Fox & Hound Jr. did great. In fact, I was amazed at how well this inexpensive device worked. The dead sockets were in the unfinished guest/maid room kitchen on the 2nd floor above the very large garage and the electrical panel was about 200ft on the first floor. at the other end of the garage building. I was able to trace the chain, which was 12 gauge Romex, through the wall to the floor and toward the back of the building. I was then able to locate the chain in the wall about 3 feet above the switch box where it seemed to stop. I cut a small hole in the drywall where the signal seemed to stop and to my surprise found the end of the cable cut off and dangling in the wall at that exact spot. Cut a wire in the wall about 4 feet from the outlet and again I cut a hole in the wall where the signal went out and the cut wire was right there. In both cases, the signal was loud enough to use the device without headphones. Just make sure the circuits you want to monitor are not live (if you're monitoring circuits). The probes feel a little light and are made out of cheap plastic, but they work great. I am very happy with it and can only recommend it.