A trolley pole is a tapered cylindrical pole of wood or metal, used to transfer electricity from a "live" overhead wire to the control and the electric traction motors of a tram or trolley bus. It is a type of current collector. The use of overhead wire in a system of current collection is reputed to be the 1880 invention of Frank J. Sprague, while the first working trolley pole was developed and demonstrated by Charles Van Depoele, in autumn 1885.