The T-781 is a explosion-proof horn speaker built-in 70v/100v transformer. The 70v/100v transformer technique reduces line losses on longer distance and allows easy parallel connection of multiple loudspeakers. The built-in horn speaker driver is designed of wide frequency response 300 to 7kHz, the rated power output 15W could meet different applications varies from room size and ambient noise surroundings. The steel enclosure and steel bracket are of red color. Easy and secure wall mount installation through the supplied mounting bracket. It is ideal choice for industrial and commercial applications in the security area of coal mine, nuclear power plant.