Here is one controversial tool, but constant use by well known TV hunters increases its acceptance as a legitimate tool daily. Basically, it searches radio frequencies via variable rate scanning. The theory is spirits can manipulate this unit and it frequencies to speak. Many investigators, including David, are beginning to pay close attention to the radio frequencies present at active locations. It is David's personal theory this is where AVPs or disembodied voices come from. We all can remember the stories of someones braces or granny's false teeth picking up radio stations reverberations. The why can't elements of our environment record and broadcast sounds when charged with emotional energy, or the spirits themselves to speak using the same energy? David uses it sparingly, but has had some surprising conversations with the spirits in the past. His main recomendation to users is be sure to budget for an external powered speaker for the unit. It has a tiny speaker and is very hard to hear without amplification. You will also have to pick up a stereo (female) to mono (male) mini-jack plug adapter to work with most modern MP3 style speakers. Radio Shack is a good source for both. David also records his sessions for missed words and EVPs that may happen during. Turn those recorders on too! It can be amazingly accurate in what it speaks, and David believes the strongest evidence of its viability is when it says words no censor would allow on Radio or TV!!