Our team has used some kind of Ovilus tool on most of our ghost hunts. Also known as the Puck, the Ovilus is an electronic speech-synthesis device which utters words depending on electromagnetic waves in the air, by using an EMF Meter.
The Ovilus has an embedded database of words. It uses electromagnetic field readings in combination to create a number. This number is used in turn to reference the database of words. The Ovilus then “speaks” that word. An Ovilus can also operate in a phonetic mode that reacts to EMF variations to create words that are not in the database.
We have found the Ovilus III used by our team on our most recent investigations to have incredible relevance to the conversations we have had with the spirit world. At least 75% of the time the words and phrases seem to be eerily accurate responses to some of our more nuanced questions. It is one of our go to tools.