Model 350 Vibratone® Emergency Horn produces a loud tone by the electro-mechanical vibration of a diaphragm. Its compact size, loud output, and heavy-duty construction make Model 350 ideal for industrial and institutional signaling applications. It’s popularly used for general alarming, start and dismissal noticing, coded paging, and process control in noisy areas.The Model 350 is enclosed in a zinc die-cast housing and sealed with gray powder-coated paint.