A Y or L shaped rod used for divining the location of water, oils, gravesites, or finding radioactive materials. Dowsing rods are sometimes used in a way not too dissimilar from a Ouija board, in which you ask a question and if the Dowsing rod moves the answer is yes. It can be made from a variety of materials.
Dowsing can also be conducted with a pendulum made of a crystal, or other materials, to find the location of materials. It works in a similar fashion to the rods, with the crystal pointing in the direction of the desired objective.
There are modern electronic Dowsing rods, notably used by the Iraqi military to detect explosives, but none have proven effective.