Abanana connectoris a single-wire electrical connector used for joining wires to equipment. The term4 mm connectoris also used, especially in Europe, although not all banana connectors will mate with 4 mm parts. The plug is a four-leafed spring tip that snaps into the jack. The plugs are frequently used to terminate patch cords for electronic test equipment. They are also often used as the plugs on the cables connecting the amplifier to the loudspeakers in hi-fi sound systems.