The PRO3000 Tone & Probe Kit is a great tool. It’s designed use is for the electronics, computer and telecommunications fields. The advantage it gives, over conventional circuit testers, is: 1) the ability to trace a circuit through one of several conduits so you don’t end up opening 10 different junction boxes to find out if the circuit you’re looking for is in here. 2) You can trace circuits without assistance, and usually faster than using conventional methods with two people. 3) You were able to locate a severed conductor inside the conduit run.
PRO3000 Tone & Probe Kit works great to find wires in walls too. To make sure you have the correct wires, simply touch them together briefly, and the tone will change, verifying that you have the correct pair.