15 Watt Amplified Horn is an alternative to 70V and 25V speaker systems. This speaker has a built in amplifier with volume control. Requires a 24V DC and a low-level audio signal. Features: Tilt and swivel bass for easy aiming, Perfect for small or large paging systems, 275 Hz - 14 kHz frequency response, Dimensions: 9" (Dia) x 9-1/4" (D).