A conical tube of light metal such as aluminum. Sometimes it is divided into sections, allowing the trumpet to collapse for storage. They can be relatively short to over a meter in length. In some instances, luminous tape or paint is applied to the larger end. It gives off a small amount of light so it can be seen in a darkened room.

The trumpet was a common tool seen in seances. The horn might levitate in a darkened room and function as a megaphone for the voices of spirits. Fraudulent mediums and mentalists have been able to recreate the phenomenon without a dependency upon non-physical entities.