Performance: Clear loud paging and tone signaling Driver: 15W compression Transformer: For 25V, 70V or 100V systems. Screwdriver-adjustable tap selector and screw terminal connections in rear. Integral strain relief and plastic cover. Enclosure: Weather-resistant assembly is all-metal construction with durable beige epoxy finish. Mounting Aids: Universal swivel mounting bracket Ships ready for installation Installation: Indoor/outdoor, surface-mount with two-wire hook-up to rear access screw terminals Operating Temperature Range: -40?F to 158?F Average Sensitivity (1W/1M): 112.2dB