I have the 2001. Ithas worked well most of the time. I have experiances the stray signal Reno spoke of many times. Noise also is a problem. I have had some older commercial building that the grounding was not so good and there is a ton of noise almost cannot hear the tone. I have not had good luck with dealing with Amprobe, as none of the local parts dealer carries them any longer, it has been troublesome to get leads that are damaged. The 2001 kit I purchased did not come with a tone generator. I had to buy that separate. It is a great asset. It is a great product, just not thrilled with Amprobe at this point.