The Bogen SPT5A is a compact, reflex horn-type loudspeakers, designed for one-way or two-way sound and communications systems.Their wide frequency response assures full-range background music reproduction, making these loudspeakers an excellent choice for multi-purpose applications, indoor or outdoor, for use in industrial plants, warehouses, schools, construction sites, transportation terminals, and recreational areas. The SPT5A has a built-in, variable impedance selector switch for matching the speaker power requirements to a 25V or 70V constant-voltage line.The SP58A has an 8-ohm impedance. The loudspeakers measure 6" in diameter and 4" deep. Connections are made through a 12" connecting cable.