The Geo Box
This is a piece of ghost hunting equipment that uses radio frequencies to help you talk to spirits.
The device scans through a range of radio frequencies at high speed. Generally, you have control of direction and speed that you scan through, so you have some control over the base line levels.
The idea behind is it that the other side can manipulate the rapidly scanned radio frequencies to produce words and sounds that we can understand. They maybe be answers to questions called out.
Again, a great tool to help build a evidence file on a possible haunting.