Ideal for showing the magnetic effects of a current flowing in a wire. A 15 cm cobalt steel magnetic needle, on an agate bearing, is mounted in a heavy wire frame supported on a stand. The wire frame has three binding posts, two of which are insulated from each other to permit current flow above or below the needle in either direction. Can be operated with any size dry cell battery (not included). Overall dimensions are 30 cm x 13 cm x 21 cm high.