metal box speakers. Rugged all-steel surface-mounted enclosure. Full range 8" cone speaker for excellent intelligibility. Compatible with 25V or 70V amplifier systems. Multiple taps at 4, 2, 1, 1/2, 1/4, 1/8 watts 4-watt maximum output power. Mounting hardware included (toggle bolts, wood screws and wire crimps). Knockouts for Wiremold. Recessed volume control at the center of front speaker grille.