Atlas Sound GA-30T 30W Utility Paging Horn Dual Voltage, Knob-Adjustable Impedance Selection for 25/70.7V Line Connection Multi-function, re-entrant horn loudspeakers offer efficient sound penetration Sturdy construction for long-term indoor and outdoor paging, music, and intercom use Entire assembly is gray with silver colored hardware Ideally suited for installation in commercial buildings, distribution centers, indoor/outdoor recreation and sports facilities, service/shop areas, gas stations and transportation terminals, and other applications where direct and efficient sound coverage is desired.